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  • 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology
  • 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
  • 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 1
    facet.materialart.
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    Towards an automatic monitoring system of infrasonic events at Mt. Etna: strategies for source location and modelling (2010)
    Springer
    Details
    Publikationsdatum: 2020-11-16
    Beschreibung: Active volcanoes characterized by open conduit conditions generate sonic and infrasonic signals, whose investigation provides useful information for both monitoring purposes and studying the dynamics of explosive processes. In this work, we discuss the automatic procedures implemented for a real-time application to the data acquired by a permanent network of five infrasound stations running at Mt. Etna volcano. The infrasound signals at Mt. Etna consist in amplitude transients, called infrasound events. The adopted procedure uses a multi-algorithm approach for event detection, counting, characterization and location. It is designed for an efficient and accurate processing of infrasound records provided by single-site and array stations. Moreover, the source mechanism of these events can be investigated off-line or in near real-time by using three different models: i) Strombolian bubble; ii) resonating conduit and iii) Helmholtz resonator. The infrasound waveforms allow us to choose the most suitable model, to get quantitative information about the source and to follow the time evolution of the source parameters.
    Beschreibung: Published
    Beschreibung: 1215–1231
    Beschreibung: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): infrasound ; monitoring system ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 2
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    Unbekannt
    Comparison of a new expert elicitation model with the Classical Model, equal weights and single experts, using a cross-validation technique (2012)
    Elsevier
    Details
    Publikationsdatum: 2021-05-17
    Beschreibung: The problem of ranking and weighting experts' performances when quantitative judgments are being elicited for decision support is considered. A new scoring model, the Expected Relative Frequency model, is presented, based on the closeness between central values provided by the expert and known values used for calibration. Using responses from experts in five different elicitation datasets, a cross-validation technique is used to compare this new approach with the Cooke Classical Model, the Equal Weights model, and individual experts. The analysis is performed using alternative reward schemes designed to capture proficiency either in quantifying uncertainty, or in estimating true central values. Results show that although there is only a limited probability that one approach is consistently better than another, the Cooke Classical Model is generally the most suitable for assessing uncertainties, whereas the new ERF model should be preferred if the goal is central value estimation accuracy.
    Beschreibung: Published
    Beschreibung: 1292-1310
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Expert elicitation ; Expert judgement ; Subjective probability ; Cross-validation ; Cooke Classical Model ; Expected Relative Frequency model ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 3
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    Unbekannt
    Seasonal cycles of seismic velocity variations detected using coda wave interferometry at Fogo volcano, São Miguel, Azores, during 2003–2004 (2010)
    Elsevier
    Details
    Publikationsdatum: 2020-11-12
    Beschreibung: Fogo volcano is an active central volcano, with a lake filled caldera, in the central part of São Miguel Island, Azores, whose current activity is limited to hydrothermal manifestations such as active fumarolic fields, thermal and CO2 cold springs and soil diffuse degassing areas. It is affected by important active tectonic structures, with high seismic activity and practically continuous micro-seismicity. A recurrent feature from the seismicity observed in volcanic regions is the occurrence of clusters of similar earthquakes, whose origin can be attributed to the repeated action of a similar source mechanism at the same focal area. Doublets/multiplets were identified in this study within a catalogue of small magnitude (usually 〈 3) volcano tectonic events recorded in 2003–2004 by a selection of stations around Fogo volcano. All events have been cross-correlated and pairs whose waveforms exhibited a cross-correlation coefficient equal to or higher than 0.9 were analysed using the coda-wave interferometry technique. Subtle velocity variations found between events highlight a seasonal cycle of the velocity patterns, with lower velocity in winter time and higher velocity during summer months. Those results, together with quantitative differences between the same doublets at different stations, exhibit an excellent correlation with rainfall. A seasonal effect can also be broadly seen in the seismicity occurrence, and some of the swarms recorded over the two year period occur during the wettest season or close to episodes of abundant (above average) rainfall. Moreover, temporal and spatial analysis of several swarms highlighted the lack of any mainshock–aftershock sequence and organized migration of the hypocenters. This is suggestive of a very heterogeneous stress field. Vp/Vs is found to be lower than usually observed in volcanic areas, an occurrence likely related to the presence of steamy fluid associated with the geothermal system. Taken together, these observations suggest that pore pressurisation plays a major role in controlling a considerable part of the recorded seismicity. The geothermal fluids around Fogo massif have been identified as derived from meteoric water, which infiltrates through Fogo Lake and the volcano flanks and flows from south to north on the northern flank. All those elements seem to point to a role played by rainfall in triggering seismicity at São Miguel, possibly through pressure changes at depth in response to surface rain and/or an interaction with the geothermal system.
    Beschreibung: Published
    Beschreibung: 231-246
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): velocity changes ; rainfall ; volcano seismicity ; triggered seismicity ; Azores archipelago ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 4
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    Statistical analysis of the volcano seismicity during the 2007 crisis of Stromboli, Italy: a 3-day oscillatory signal as onset of the activity (2010)
    AGU
    Details
    Publikationsdatum: 2020-11-17
    Beschreibung: We analyze the volcano seismicity recorded during the 2007 eruption of Stromboli. Data-set is composed of the continuous recordings of a three-component broad-band seismometer and of a strainmeter. Starting from the characterization of the standard activity as a stationary phase of equilibrium, we investigate the non-equilibrium phase of the effusive process. A statistical analysis of the explosions reveals that the occurrence is always driven by a Poisson process as for the standard activity, even approaching the effusion phase, with the only difference in shortening the inter-times just during the effusion. A slightly different process can be advocated for the swarms of the explosions, because a maximum in the distribution of inter-times can be evidenced. Regarding the amplitudes of the explosion-quakes, they have a log-normal distribution until the effusion onset as in the standard Strombolian activity. The actual departure from that stationarity seems to be traced by an early deformative response at very long period. It appears as a transient oscillating signal characterized by a period of about three days that modulates the explosion amplitudes. In a conceptual organ pipe-like model it is related to the chocking of the pipe. The successive activity can be interpreted as the response of volcano to restore the equilibrium condition.
    Beschreibung: Published
    Beschreibung: B09312
    Beschreibung: 1V. Storia eruttiva
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Stromboli ; eruption ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 5
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    Tornillos at Vulcano: Clues to the dynamics of the hydrothermal system (2010)
    Elsevier
    Details
    Publikationsdatum: 2020-11-12
    Beschreibung: The number of tornillo events has recently increased at the Vulcano Island, Italy. While only 15 tornillos were recorded during 2004–2006, 584 events occurred in 2007–2008. They were located just below La Fossa Crater at depths ranging between 0.1 and 1 km b.s.l. During two intervals in 2007–2008 increases in the number of tornillos took place at the same time as temperature and geochemical anomalies were observed. The spectral content of the tornillos, generally characterized by one–two dominant spectral peaks near 6 and 10 Hz, varied over time, with changes also noted in the quality factors. The simplest source mechanism proposed for tornillos is the free eigenvibration of a fluid volume within a crack or a conduit. Based on this model, we propose a causal relationship between the temperature and geochemical anomalies and the increases in numbers of tornillos. As the amount of hydrothermal fluids increases during the anomalies, the upward flux of fluids grows. The consequent changes in the pressure, temperature and dynamics of the system of cracks and conduits result in the generation of tornillos. Based on the fluid-filled crack/conduit model, the shallow depths of the sources and the values of the quality factors, the fluid within the resonant crack/conduit was inferred to be an ash–gas or water droplet–gas mixture. Moreover, the observed variations in the wavefield can be caused by small changes in the location of the source, in the source mechanism, or in the medium in between the source and the seismic station. Finally, another peculiar feature of tornillos is the amplitude modulation that can be explained as a result of a beating phenomenon.
    Beschreibung: Published
    Beschreibung: 377-393
    Beschreibung: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Tornillos ; Vulcano Island ; Hydrothermal system ; Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 6
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    Influence of inherited geometry and fault history on the seismogenic activity and potential of strike-slip fault systems in NW Slovenia: the case study of the Ravne Fault (2010)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: La zona di faglia Ravne è situata in un area di interazione fra due sistemi regionali di faglie con differente cinematica, entrambi collegati alla convergenza fra Adria e Eurasia: le faglie dinariche orientate NW-SE e le faglie del Sud-alpino orientate E-W. L’analisi di dati di geologia strutturale e di due sequenze sismiche recenti che hanno colpito l’area, ci permette di proporre un modello sismotettonico per la faglia di Ravne, che è stata interessata da diverse fasi tettoniche. La geometria originale e la storia evolutiva della zona di faglia svolgono un ruolo cruciale nella distribuzione recente dell’attività sismica e del potenziale sismogenetico dell’intera struttura. Infatti, la configurazione attuale della faglia Ravne, caratterizzata da fagliazione trascorrente su piani ad alto angolo a profondità crostali, è il risultato dell’iniziale geometria di un thrust orientato NW-SE e avente immersione verso NE, e della sua interazione con i piani di thrust diretti essenzialmente E-W. Partendo dai dati raccolti e tenendo in considerazione sia il quadro geodinamico che le relazioni empiriche, proponiamo tre possibili scenari con relativi potenziali sismogenetici per la possibile futura attività della faglia di Ravne.
    Beschreibung: Published
    Beschreibung: Udine
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: open
    Schlagwort(e): Ravne Fault ; Western Slovenia ; fault growth ; linkage processes ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Extended abstract
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  • 7
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    Static stress drop associated with brittle slip events on exhumed faults. (2010)
    AGU
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We estimate the static stress drop on small exhumed strike-slip faults in the Lake Edison granodiorite of the central Sierra Nevada (California). The subvertical strike-slip faults were exhumed from 4 to 15 km depth and were chosen because they are exposed in outcrop along their entire tip-to-tip lengths of 8–12 m. Slip nucleated on joints and accumulated by crystal-plastic shearing (forming quartz mylonites from early quartz vein filling in joints) and successive brittle faulting (forming epidote-bearing cataclasites). The occurrence of thin, 300 mm wide, pseudotachylytes along some small faults throughout the study area suggests that some, if not all, of the brittle slip on the study area faults may have been seismic. We suggest that the contribution of brittle, cataclastic slip to the total slip along the studied cataclasite-bearing small faults may be estimated by the length of epidote-filled, rhombohedral dilatational jogs (rhombochasms) distributed quasi-periodically along the length of the faults. The interpretation that slip recorded by rhombochasms occurred in single events is based on evidence that (1) epidote crystals are randomly oriented and undeformed within the rhombochasm; (2) cataclasite in principal slip zones does not include clasts of previous cataclasite, and (3) rhombochasm lengths vary systematically along the length of the faults with slip maximum occurring near the fault center, tapering to the fault tips. We thereby constrain both the rupture length and slip. On the basis of these measurements, we calculate stress drops ranging over 90–250 MPa, i.e., one to two orders of magnitude larger than typical seismological estimates for earthquakes, but similar in magnitude to seismological estimates of small (〈M2) earthquakes from the San Andreas Fault Observatory at Depth (SAFOD). The slip events described in the present study occurred along small, deep-seated faults, and, given the calculated stress drops and observations that brittle faults exploited joints sealed by quartz-bearing mylonite, we conclude that these were ‘‘strong’’ faults.
    Beschreibung: Published
    Beschreibung: B02402
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): earthquakes ; stress drops ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 8
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    Effects of the 1989 fracture system in the dynamics of the upper SE flank of Etna revealed by volcanic tremor data: The missing link? (2010)
    AGU
    Details
    Publikationsdatum: 2012-02-03
    Beschreibung: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.
    Beschreibung: Fracture reactivation is a widespread process in nature even though evidence of magma-induced reactivation is less documented. Here we provide evidence of the reactivation of a fracture system on the upper flank of the Mt. Etna volcano and consider its possible implications in understanding the recent volcanic and tectonic activity. A NNW–SSE trending fracture, partly accompanied by magma emplacement in the form of a laterally propagating dike, formed in 1989 on the upper SE flank of Etna. Lava effusions in 1991–1993, 2001, and 2006 were associated with volcano-tectonic (VT) seismicity and ground deformations on the upper part of the volcano, which document the seismogenetic involvement of the 1989 fractures, although without eruptive phenomena along the discontinuity. In addition to the aforementioned episodes of VT seismicity, differences in the characteristics of the background seismic radiation (volcanic tremor) were measured at stations close to these fractures during the eruptive activity on 24 November 2006, for which more detailed volcanological and seismological time histories are available. Moving on from these findings, we analyze volcanic tremor data recorded close to the summit and along the S flank of the volcano to highlight the interactions between seismic radiation and the 1989 fracture system. Centroid location of volcanic tremor and wave field characteristics at stations of the permanent local seismic network of Etna highlight the guidance role played by the 1989 fractures during the eruptive activity on 24 November 2006. In addition, the collected data shed light on hitherto unknown structural features, which appear to connect the volcano summit to the lower SE slope and also play an important role in controlling the instability of the E flank. More generally, this study shows how (1) using an integrated approach, it is possible to link apparently different features to a common structure, showing uniform and distinct dynamics relevant at the volcano scale, and (2) fracture reactivation can also occur by means of magma intrusion, playing an important role in the transfer of magma within a volcanic edifice.
    Beschreibung: Published
    Beschreibung: B11306
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mount Etna ; fracture system ; volcanic tremor ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 9
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    Evolution of an active lava flow field using a multitemporal LIDAR acquisition (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2012-02-03
    Beschreibung: Application of light detection and ranging (LIDAR) technology in volcanology has 7 developed rapidly over the past few years, being extremely useful for the generation 8 of high‐spatial‐resolution digital elevation models and for mapping eruption products. 9 However, LIDAR can also be used to yield detailed information about the dynamics of 10 lava movement, emplacement processes occuring across an active lava flow field, and the 11 volumes involved. Here we present the results of a multitemporal airborne LIDAR survey 12 flown to acquire data for an active flow field separated by time intervals ranging from 13 15 min to 25 h. Overflights were carried out over 2 d during the 2006 eruption of Mt. Etna, 14 Italy, coincident with lava emission from three ephemeral vent zones to feed lava flow in 15 six channels. In total 53 LIDAR images were collected, allowing us to track the volumetric 16 evolution of the entire flow field with temporal resolutions as low as ∼15 min and at a 17 spatial resolution of 〈1 m. This, together with accurate correction for systematic errors, 18 finely tuned DEM‐to‐DEM coregistration and an accurate residual error assessment, 19 permitted the quantification of the volumetric changes occuring across the flow field. We 20 record a characteristic flow emplacement mode, whereby flow front advance and channel 21 construction is fed by a series of volume pulses from the master vent. Volume pulses 22 have a characteristic morphology represented by a wave that moves down the channel 23 modifying existing channel‐levee constructs across the proximal‐medial zone and building 24 new ones in the distal zone. Our high‐resolution multitemporal LIDAR‐derived DEMs 25 allow calculation of the time‐averaged discharge rates associated with such a pulsed flow 26 emplacement regime, with errors under 1% for daily averaged values.
    Beschreibung: This work was partially funded by the Italian 930 Dipartimento della Protezione Civile in the frame of the 2007–2009 Agree- 931 ment with Istituto Nazionale di Geofisica e Vulcanologia–INGV. A.F. 932 benefited from the MIUR‐FIRB project “Piattaforma di ricerca multi‐disci- 933 plinare su terremoti e vulcani (AIRPLANE)” n. RBPR05B2ZJ. S.T. 934 benefited from the project FIRB “Sviluppo di nuove tecnologie per la prote- 935 zione e difesa del territorio dai rischi naturali (FUMO)” funded by the Italian 936 Ministero dell’Istruzione, dell’Università e della Ricerca.
    Beschreibung: Published
    Beschreibung: B11203
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): LIDAR ; lava flow ; Etna ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Morphometry of scoria cones located on a volcano flank: A case study from Mt. Etna (Italy), based on high-resolution LiDAR data (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: By using new high-resolution (2 m) digital elevation model derived from the 2005 LiDAR survey of Mt. Etna volcano (Italy), our study measured the classical morphometrical parameters for scoria cones, i.e. Wco (cone width), Wcr (crater diameter), H (cone height) as well as volume, inclination of cone slope and substrate, and a number of other parameters for 135 scoria cones of Mt. Etna. Volume and age distribution of cones shows that there is no direct structural control on their emplacement in terms of Etna's rift zones. The cones are progressively smaller in size toward summit, which can be explained by the large volcano's feeding system and progressively frequent lava burial toward top. A careful analysis of H/Wco ratio (determined as 0.18 for other volcanic fields worldwide) shows that this ratio strongly depends on (1) the calculation method of H and (2) lava burial of cone. For Etnean cones, applying an improved method for calculating H relative to the dipping substrate results in a significantly lowered standard H/Wco ratio (0.137), which in turn questions the validity of the classical value of 0.18 in the case of large central volcanoes. The reduction of the ratio is not only due to methodology but also to the common lava burial. This can be expressed even better if Hmean is used instead of Hmax (Hmean/Wco = 0.098). Using this measure, at Etna, well formed cones have higher ratios than structurally deformed (e. g. double or rifted) cones. Furthermore, although the sampled scoria cones at Etna have formed in a relatively narrow time interval (〈 6500 yrs BP), there is a slight decrease in H/Wco corresponding to erosional changes detected globally (H/Wco = 0.143, 0.135 and 0.115 for three age classes of Etna's scoria cones, corresponding to average slopes of 26.6, 23.9 and 23.7°). Because the morphometrical effect of position on a dipping substrate as well as lava burial exceeds the effect of erosion, we call attention to use caution in simply using the H/Wco ratio of scoria cones for detecting age, especially on large active volcanoes.
    Beschreibung: Published
    Beschreibung: 320-330
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): scoria cone ; morphometry ; Etna ; H/Wco ratio ; DEM analysis ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.06. Methods::05.06.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 11
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    Predicting the impact of lava flows at Mount Etna, Italy (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Forecasting the time, nature, and impact of future eruptions is difficult at volcanoes such as Mount Etna, in Italy, where eruptions occur from the summit and on the flanks, affecting areas distant from each other. Nonetheless, the identification and quantification of areas at risk from new eruptions are fundamental for mitigating potential human casualties and material damage. Here, we present new results from the application of a methodology to define flexible high‐resolution lava invasion susceptibility maps based on a reliable computational model for simulating lava flows at Etna and on a validation procedure for assessing the correctness of susceptibility mapping in the study area. Furthermore, specific scenarios can be extracted at any time from the simulation database, for land use and civil defense planning in the long term, to quantify, in real time, the impact of an imminent eruption, and to assess the efficiency of protective measures.
    Beschreibung: This work was sponsored by the Italian Ministry for Education, University and Research, FIRB project RBAU01RMZ4 “Lava flow simulations by Cellular Automata,” and by the National Civil Defense Department and INGV (National Institute of Geophysics and Volcanology), project V3_6/09 “V3_6 – Etna.”
    Beschreibung: Published
    Beschreibung: B04203
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: 4.4. Scenari e mitigazione del rischio ambientale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): lava flows ; volcanic hazard ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 12
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    LIDAR strip adjustment: Application to volcanic areas (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: DEMs derived from LIDAR data are nowadays largely used for quantitative analyses and modelling in geology and geomorphology. High-quality DEMs are required for the accurate morphometric and volumetric measurement of land features. We propose a rigorous automatic algorithm for correcting systematic errors in LIDAR data in order to assess sub-metric variations in surface morphology over wide areas, such as those associated with landslide, slump, and volcanic deposits. Our procedure does not require a priori knowledge of the surface, such as the presence of known ground control points. Systematic errors are detected on the basis of distortions in the areas of overlap among different strips. Discrepancies between overlapping strips are assessed at a number of chosen computational tie points. At each tie point a local surface is constructed for each strip containing the point. Displacements between different strips are then calculated at each tie point, and minimization of these discrepancies allows the identification of major systematic errors. These errors are identified as a function of the variables that describe the data acquisition system. Significant errors mainly caused by a non-constant misestimation of the roll angle are highlighted and corrected. Comparison of DEMs constructed using first uncorrected and then corrected LIDAR data from different Mt. Etna surveys shows a meaningful improvement in quality: most of the systematic errors are removed and the accuracy of morphometric and volumetric measurements of volcanic features increases. These corrections are particularly important for the following studies of Mt. Etna: calculation of lava flow volume; calculation of erosion and deposition volume of pyroclastic cones; mapping of areas newly covered by volcanic ash; and morphological evolution of a portion of an active lava field over a short time span.
    Beschreibung: Published
    Beschreibung: 123-135
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): LIDAR ; Calibration ; DEM ; Etna ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.06. Methods::05.06.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
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    Seismic tremor in subduction zones: the rock-physics evidence (2010)
    AGU
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: Episodic tremor and slip (ETS) have been correlated with rupture phenomena in subducting oceanic lithosphere at 30–45 km depth, where high VP/VS ratios, which suggest high-fluid pressures, have been observed. ETS, by accommodating slip in the down-dip portion of the subduction zone, may trigger megathrust earthquakes up-dip in the locked section. During dehydration experiments on serpentinite (typical rock of the oceanic lithosphere) at temperatures found in nature at 30–45 km depth (400– 550 C), we observe seismic signals in the form of acoustic emissions that closely resemble low frequency earthquakes, seismic tremor and regular earthquakes. Our findings support the concept that water released during dehydration reactions increases the pore pressures and can trigger ETS and regular earthquakes by reducing slip resistance. Citation: Burlini, L., G. Di Toro, and P. Meredith (2009), Seismic tremor in subduction zones: Rock physics evidence, Geophys. Res. Lett., 36, L08305, doi:10.1029/2009GL037735.
    Beschreibung: Published
    Beschreibung: L08305
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Non volcanic tremor ; dehydration reactions ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
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    Unbekannt
    The effects of fault orientation and fluid infiltration on fault rock assemblages at seismogenic depths (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The factors controlling the development of different types of fault rock assemblages and, more specifically, the formation of friction melts are still not fully understood. In this study we compared two exhumed strike–slip faults in the Adamello batholith (Southern Alps): the Gole Larghe and the Passo Cercen fault zones, active at 9–11 km depth and temperatures of 250–300 C. Each fault zone consists of hundreds of sub-parallel strands exploiting pre-existing joints. The Gole Larghe fault strikes N105 5 and is dextral; the fault rocks are cataclasites and widespread, centimetre-thick pseudotachylytes. The Passo Cercen fault strikes on average N130 and is formed by multiple fault horizons: fault segments striking N105 –N130 are mainly dextral, whereas faults striking N135 –N140 are mainly sinistral. Microstructural, mineralogical and geochemical investigations show that the fault rocks are cataclasites associated with thick epidote þ K-feldspar þ quartz veins and rare, millimetre-thick pseudotachylytes. Field evidence suggests that in both fault zones, the direction of the maximum horizontal stress s1 was N135 . The Gole Larghe fault strikes at about 30 to s1 and is favourably oriented for reactivation. By contrast, the Passo Cercen fault strikes at low angles to s1 and is unfavourably oriented for reactivation, therefore requiring the development of high pore pressures, as suggested by the occurrence of extensive epidote veining and hydraulic breccias. It is proposed that frictional melting in the Passo Cercen fault zone was inhibited by the development of high pore pressures and low effective normal stresses.
    Beschreibung: Published
    Beschreibung: 1511-1524
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): earthquakes ; pseudotachylytes ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
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    Unbekannt
    Rough Faults, Distributed Weakening, and Off-Fault Deformation (2010)
    AGU
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We report systematic spatial variations of fault rocks along non-planar strike-slip faults 11 cross-cutting the Lake Edison Granodiorite, Sierra Nevada, California (Sierran wavy fault) and 12 Lobbia outcrops of the Adamello Batholith in the Italian Alps (Lobbia wavy fault). In the case of 13 the Sierran fault, pseudotachylyte formed at contractional fault bends, where it is found as thin 14 (1-2 mm) fault-parallel veins. Epidote and chlorite developed in the same seismic context as the 15 pseudotachylyte and are especially abundant in extensional fault bends. We argue that the 16 presence of fluids, as illustrated by this example, does not necessarily preclude the development 17 of frictional melt. In the case of the Lobbia fault, pseudotachylyte thickness varies along the 18 length of the fault, but the pseudotachylyte veins thicken and pool in extensional bends. We 19 conduct a quantitative analysis of fault roughness, microcrack distribution, stress, and friction 20 along the Lobbia fault. 21 Numerical modeling results show that opening in extensional bends and localized thermal 22 weakening in contractional bends counteract resistance encountered by fault waviness, resulting 23 in an overall weaker fault than suggested by the corresponding static friction coefficient. The 24 models also predict static stress redistribution around bends in the faults which are consistent 25 with distributions of microcracks, indicating significant elastic and inelastic strain energy is 26 dissipated into the wall rocks due to non-planar fault geometry. Together these observations suggest that damage and energy dissipation occurs along the entire non-planar fault during slip, 28 rather than being confined to the region close to the dynamically propagating crack tip.
    Beschreibung: Published
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): earthquakes ; rutpure ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
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    Patterns in the recent 2007–2008 activity of Mount Etna volcano investigated by integrated geophysical and geochemical observations (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2012-02-03
    Beschreibung: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union
    Beschreibung: Seismic, deformation, and volcanic gas observations offer independent and complementary information on the activity state and dynamics of quiescent and eruptive volcanoes and thus all contribute to volcanic risk assessment. In spite of their wide use, there have been only a few efforts to systematically integrate and compare the results of these different monitoring techniques. Here we combine seismic (volcanic tremor and long‐period seismicity), deformation (GPS), and geochemical (volcanic gas plume CO2/SO2 ratios) measurements in an attempt to interpret trends in the recent (2007–2008) activity of Etna volcano. We show that each eruptive episode occurring at the Southeast Crater (SEC) was preceded by a cyclic phase of increase‐decrease of plume CO2/SO2 ratios and by inflation of the volcano’s summit captured by the GPS network. These observations are interpreted as reflecting the persistent supply of CO2‐rich gas bubbles (and eventually more primitive magmas) to a shallow (depth of 1–2.8 km asl) magma storage zone below the volcano’s central craters (CCs). Overpressuring of the resident magma stored in the upper CCs’ conduit triggers further magma ascent and finally eruption at SEC, a process which we capture as an abrupt increase in tremor amplitude, an upward (〉2800 m asl) and eastward migration of the source location of seismic tremor, and a rapid contraction of the volcano’s summit. Resumption of volcanic activity at SEC was also systematically anticipated by declining plume CO2/SO2 ratios, consistent with magma degassing being diverted from the central conduit area (toward SEC).
    Beschreibung: Published
    Beschreibung: Q09008
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): volcano monitoring ; Mt. Etna volcano ; geochemistry and geophysics ; volcanic tremor ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
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    Unbekannt
    Response of Mount Etna to dynamic stresses from distant earthquakes (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2012-02-03
    Beschreibung: Influences of distant earthquakes on volcanic systems by dynamic stress transfer are well documented. We analyzed seismic signals and volcanic activity at Mount Etna during two periods, January 2006 and May 2008, that clearly showed variations coincident with distant earthquakes. In the first period, characterized by mild volcano activity, the effect of the dynamic stress transfer, caused by an earthquake in Greece (M = 6.8), was twofold: (1) banded tremor activity changed its features and almost disappeared; (2) a swarm of volcano‐tectonic (VT) earthquakes took place. The changes of the banded tremor were likely due to variations in rock permeability, caused by fluid flows driven by dynamic strain. The VT earthquake swarm probably developed as a secondary process, promoted by the dynamically triggered activation of magmatic fluids. The second period, May 2008, showed an intense explosive activity. During this interval, the dynamic stress transfer, associated with the arrival of the seismic waves of the Sichuan earthquake (M = 7.9), affected the character of the seismo‐volcanic signals and on the following day triggered an eruption. In particular, we observed changes in volcanic tremor and increases of both occurrence rate and energy of long period events. In this case, we suggest that dynamic stress transfer caused nucleation of new bubbles in volatile‐rich magma bodies with consequent buildup of pressure, highlighted by the increase of long period activity, followed by the occurrence of an eruption. We conclude that stresses from distant earthquakes are capable of modifying the state of the volcano.
    Beschreibung: Published
    Beschreibung: B12304
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mt. Etna volcano ; dynamic stress transfer ; triggered eruption ; triggered seismicity ; volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
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    Unbekannt
    Anatomy of an unstable volcano from InSAR: Multiple processes affecting flank instability at Mt. Etna, 1994–2008 (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2012-02-03
    Beschreibung: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.
    Beschreibung: Volcano deformation may occur under different conditions. To understand how a volcano deforms, as well as relations with magmatic activity, we studied Mt. Etna in detail using interferometric synthetic aperture radar (InSAR) data from 1994 to 2008. From 1994 to 2000, the volcano inflated with a linear behavior. The inflation was accompanied by eastward and westward slip on the eastern and western flanks, respectively. The portions proximal to the summit showed higher inflation rates, whereas the distal portions showed several sectors bounded by faults, in some cases behaving as rigid blocks. From 2000 to 2003, the deformation became nonlinear, especially on the proximal eastern and western flanks, showing marked eastward and westward displacements, respectively. This behavior resulted from the deformation induced by the emplacement of feeder dikes during the 2001 and 2002–2003 eruptions. From 2003 to 2008, the deformation approached linearity again, even though the overall pattern continued to be influenced by the emplacement of the dikes from 2001 to 2002. The eastward velocity on the eastern flank showed a marked asymmetry between the faster sectors to the north and those (largely inactive) to the south. In addition, from 1994 to 2008 part of the volcano base (south, west, and north lower slopes) experienced a consistent trend of uplift on the order of ∼0.5 cm/yr. This study reveals that the flanks of Etna have undergone a complex instability resulting from three main processes. In the long term (103–104 years), the load of the volcano is responsible for the development of a peripheral bulge. In the intermediate term (≤101 years, observed from 1994 to 2000), inflation due to the accumulation of magma induces a moderate and linear uplift and outward slip of the flanks. In the short term (≤1 year, observed from 2001 to 2002), the emplacement of feeder dikes along the NE and south rifts results in a nonlinear, focused, and asymmetric deformation on the eastern and western flanks. Deformation due to flank instability is widespread at Mt. Etna, regardless of volcanic activity, and remains by far the predominant type of deformation on the volcano.
    Beschreibung: ESA provided the SAR data (Cat‐1 no. 4532 and GEO Supersite initiative). The DEM was obtained from the SRTM archive, while the ERS‐1/2 orbits are courtesy of the TU‐Delft, The Netherlands. This work was partially funded by INGV and the Italian DPC (DPCINGV project V4 “Flank”), the Italian DPC (under special agreement with IREA‐CNR), and the Italian Space Agency under contract “sistema rischio vulcanico (SRV).” The authors thank Francesco Casu, Paolo Berardino, and Riccardo Lanari for their support and Geoff Wadge and Michael Poland for their helpful and constructive review of the manuscript.
    Beschreibung: Published
    Beschreibung: B10405
    Beschreibung: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Flank instability ; InSAR ; volcanoes ; Etna ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.04. Instrumentation and techniques of general interest::05.04.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
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    Predicting the impact of lava flows at Mount Etna (Italy) (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Forecasting the time, nature and impact of future eruptions is difficult at volcanoes such as Mount Etna, in Italy, where eruptions occur from the summit and on the flanks, affecting areas distant from each other. Nonetheless, the identification and quantification of areas at risk from new eruptions is fundamental for mitigating potential human casualties and material damage. Here, we present new results from the application of a methodology to define flexible high-resolution lava invasion susceptibility maps based on a reliable computational model for simulating lava flows at Etna and on a validation procedure for assessing the correctness of susceptibility mapping in the study area. Furthermore, specific scenarios can be extracted at any time from the simulation database, for land-use and civil defence planning in the long-term, to quantify, in real-time, the impact of an imminent eruption, and to assess the efficiency of protective measures.
    Beschreibung: This work was sponsored by the Italian Ministry for Education, University and Research, FIRB project n° RBAU01RMZ4 “Lava flow simulations by Cellular Automata”, and by the National Civil Defence Department and INGV (National Institute of Geophysics and Volcanology), project V3_6/09 “V3_6 – Etna”.
    Beschreibung: In press
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: 4.4. Scenari e mitigazione del rischio ambientale
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): lava flows ; Etna ; hazard evaluation ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
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    Crustal changes at Mt. Etna volcano accompanying the 2002–2003 eruption as inferred from a repeating earthquake analysis (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In this work, waveform variations in repeating volcanotectonic earthquakes occurring from 2001–2009 in the northeastern flank of Mt. Etna were studied. Changes in waveform were found mainly during 2002–2003; and consisted of a decreasing similarity in the coda of events in earthquake families, as revealed by cross-correlation analysis, and delays, increasing proportionally to the lapse time, detected by coda wave interferometry. Such variations, mainly evident at stations located in the north-eastern flank of the volcano, were likely due to medium changes taking place within this region. Localized medium velocity decreases were inferred to occur in 2002–2003, followed by successive increases. The velocity decrease was interpreted as being caused by the opening or enlargement of cracks, produced by intruding magma bodies, intense ground deformation, and/ or VT earthquake activity that accompanied the 2002–2003 Mt. Etna eruption. On the other hand, subsequent velocity increases were interpreted as resulting from healing processes.
    Beschreibung: Published
    Beschreibung: L18311
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): coda wave interferometry ; Etna ; VT earthquakes ; Pernicana fault ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 21
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    Geometry and modeling of an active offshore thrust-related fold system: the Amendolara Ridge, Ionian Sea, southern Italy (2012)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: On the Ionian Sea coast of southern Italy, spanning the transition from the Calabrian Arc to the Apennines, NE-directed motion of the thin-skinned frontal thrust belt of the Apennines toward the Apulian foreland reportedly ceased during the Early-Middle Pleistocene. The submarine extension of the frontal thrust belt is represented by the Amendolara ridge, which stretches for over 80 km to the SE beneath the Taranto Gulf. High-resolution marine geophysical data collected on the Amendolara ridge during the TEATIOCA_2011 cruise provided unequivocal constraints to assert active fault-related fold growth. Single-channel seismic (sparker) and acoustic CHIRP profiles, corroborated by multibeam mapping and shallow coring, form the novel dataset to constrain the near-bottom evolution. The new data were benchmarked to the crustal geometry by means of interpretation of existing multichannel seismic profiles.
    Beschreibung: Published
    Beschreibung: Arcavacata di Rende (CS)
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: open
    Schlagwort(e): Active fault-propagation folds ; Blind faults ; Seismogenic sources ; Jonian Sea ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Extended abstract
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  • 22
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    Towards an Automatic Monitoring System of Infrasonic Events at Mt. Etna: Strategies for Source Location and Modeling (2010)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Active volcanoes characterized by open conduit conditions generate sonic and infrasonic signals, whose investigation provides useful information for both monitoring purposes and studying the dynamics of explosive processes. In this work, we discuss the automatic procedures implemented for a real-time application to the data acquired by a permanent network of five infrasound stations running at Mt. Etna volcano. The infrasound signals at Mt. Etna consist in amplitude transients, called infrasound events. The adopted procedure uses a multi-algorithm approach for event detection, counting, characterization and location. It is designed for an efficient and accurate processing of infrasound records provided by single-site and array stations. Moreover, the source mechanism of these events can be investigated off-line or in near real-time by using three different models: (1) Strombolian bubble; (2) resonating conduit and (3) Helmholtz resonator. The infrasound waveforms allow us to choose the most suitable model, to get quantitative information about the source and to follow the time evolution of the source parameters.
    Beschreibung: Published
    Beschreibung: 1215–1231
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Infrasound ; monitoring system ; Mt. Etna volcano ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 23
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    New insights into banded tremor from the 2008–2009 Mount Etna eruption (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We investigated the banded tremor activity occurring at Mt. Etna volcano between August-October 2008 during the 2008-2009 eruption. The banded tremor occurred in episodes lasting 25-30 minutes with intervals in between the episodes of about 25 minutes. Seismic signal analyses showed that the banded tremor was characterised by spectral contents, wavefields and source locations that differed from the “ordinary” volcanic tremor. The infrasound recordings exhibited an intermittent infrasonic tremor alternating with the banded tremor episodes. Finally, nonlinear analyses suggested that banded tremor system can be considered chaotic, implying: i) sensitive dependence on initial conditions, suggesting not only that a banded tremor system requires particular conditions to generate, but also that slight variations of these conditions are able to greatly change the features of the banded tremor or even to stop it; ii) long-term unpredictability, that is, the impossibility to forecast the long-term evolution of the banded tremor. On the basis of all these results and analogies with geyser models, we suggest a model of banded tremor that invokes alternating recharge-discharge phases. Banded tremor is due to “perturbations” in shallow aquifers, such as fluid movement and bubble growth or collapse due to hydrothermal boiling, triggered by the heat and hot fluid transfer from the underlying magma bodies. This heat-fluid transfer also causes an increasing pressure in the aquifer leading to fluid-discharge. During this process the seismic radiation decreases and, if the fluid-discharge is well coupled with the atmosphere, acoustic signals are generated.
    Beschreibung: Published
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Banded tremor ; Mt. Etna volcano ; volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 24
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    Magma dynamics of 2007 Stromboli effusive eruption as revealed by high precision location of seismic events. (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Stromboli is considered one of the most active volcanoes in the world, and its persistent but moderate explosive activity is only interrupted by occasional episodes of more vigorous activity accompanied by lava flows. A new effusive eruption began in late February, 2007 and was characterised by intense seismic activity throughout the whole period. The accurate seismic signals analysis showed the presence of families of events with similar waveform signatures (i.e. multiplets) located beneath the crater region. Since traditional location techniques do not allow obtaining reliable hypocentres, our analysis focused on high precision locations of the seismicity, in order to better define the source geometry of the events. Hypocentres, therefore, have been relocated considering two steps: the first, based on a robust probabilistic approach, is used to find the absolute position of the clusters; the second exploits a master-event concept for the relative location of the events. Finally, the shape of the clusters and the temporal migration of the foci were correlated with the eruptive phases. The results show that the occurrence of a cluster of events is related to the opening and closure of a vent opened in the Sciara del Fuoco slope and, in particular, to the intrusion of a dike injected by central conduit in a radial direction, whereas another cluster lies in a narrow vertical volume positioned under the crater area. The geometry of the clusters suggests a source region depicting the shallower feeding system. Overall, the results highlight that the high precision locations method is an efficient and quick tool to obtain a better understanding of the magmatic processes occurring during an ongoing eruption.
    Beschreibung: Published
    Beschreibung: 405-415
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): eruption ; high precision location ; seismic swarms ; magma dynamics ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
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    Geological evolution of a complex basaltic stratovolcano: (2012)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: An updated geological evolution model is presented for the composite basaltic stratovolcano of Mount Etna. It was developed on the basis of the stratigraphic setting proposed in the new geological map that was constrained by 40Ar/39Ar age determinations. Unconformitybounded stratigraphy allows highlighting four main evolutionary phases of eruptive activity in the Etna region. The Basal Tholeiitic Supersynthem corresponds to a period, from about 500 to 330 ka, of scattered fissure-type eruptions occurring initially in the foredeep basin and then in a subaerial environment. From about 220 ka, an increase in the eruptive activity built a lava-shield during the Timpe Supersynthem. The central-type activity occurred at least 110 ka ago through the Valle del Bove Supersynthem. The earliest volcanic centres recognized are Tarderia, Rocche and Trifoglietto and later Monte Cerasa, Giannicola, Salifizio and Cuvigghiuni. During the Stratovolcano Supersynthem, from about 57 ka ago, the intense eruptive activity of Ellittico volcano formed a roughly 3600 m-high stratocone that expanded laterally, filling the Alcantara and Simeto paleovalleys. Finally, effusive activity of the last 15 ka built the Mongibello volcano. Its eruptive activity is mainly concentrated in three weakness zones in which the recurrent magma intrusion generates flank eruptions down to low altitude. The four main evolutionary phases may furnish constraints to future models on the origin of Etna volcano and help unravel the geodynamic puzzle of eastern Sicily.
    Beschreibung: Published
    Beschreibung: 306-317
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mount Etna, geological evolution, stratigraphy, ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 26
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    Unbekannt
    Geological map of Etna volcano, 1:50,000 scale (2012)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The new geological map of Etna volcano at 1:50,000 scale represents a significant progress in the geological studies of this volcano over the last 30 years, coming after Waltershausen’s map published around the mid of 19th century, the first geological map of a large active volcano, and the ROMANO et alii (1979) map published about a century later, both at 1:50,000 scale. Lithostratigraphy was used for mapping volcanic units and then Unconformity Bounded Units were applied to group lithostratigraphic units into synthems. In addition, lithosomes were exploited to better represent the spatial localization of different eruptive centres according to their morphology. On the whole, we identified 27 lithostratigraphic units, grouped into 8 synthems, and 9 volcanoes. In detail, effusive and explosive deposits generated by each eruption of Mongibello and, partially, Ellittico volcanoes were mapped as flow rank. This stratigraphic framework represents the best synthesis of the geological evolution of Etna volcano using the main unconformities recognized within its complex volcanic succession. In addition, we constrain the Etna volcanic succession and its lithostratigraphic units chronologically by radioisotope age determinations. On the basis of the outlined synthemic units, it was possible to divide Etna’s volcanic succession into 4 supersynthems, which correspond to 4 well-defined and spatially localized phases. The detailed reconstruction of the past eruptive activity allowed compiling the most accurate dataset in particular of the Holocene eruptions of Etna volcano, which will enable significantly improving the volcanic hazard assessment, together with petrological interpretation of erupted magmas and geophysical modelling of the volcano plumbing system.
    Beschreibung: Published
    Beschreibung: 265-291
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mount Etna, geological map, basaltic composite ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 27
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    Flank instability structure of Mt. Etna inferred by a magnetotelluric survey (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: This paper presents a magnetotelluric (MT) survey of the unstable eastern flank of Mt. Etna. We take thirty soundings along two profiles oriented in the N-S and NW-SE directions, and from these data recover two 2D resistivity models of the subsurface. Both models reveal three major layers in a resistive-conductive-resistive sequence, the deepest extending to 14 km bsl. The shallow layer corresponds to the volcanic cover, and the intermediate conductive layer corresponds to underlying sediments segmented by faults. These two electrical units are cut by E-W-striking faults. The third layer (basement) is interpreted as mainly pertinent to the Apennine-Maghrebian Chain associated with SW-NE-striking regional faults. The detailed shapes of the resistivity profiles clearly show that the NE Rift is shallow-rooted ( 0–1 km bsl), thus presumably fed by lateral dikes from the central volcano conduit. The NW-SE profile suggests by a series of listric faults reaching up to 3 km bsl, then becoming almost horizontal. Toward the SE, the resistive basement dramatically dips (from 3 km to 10 km bsl), in correspondence with the Timpe Fault System. Several high-conductivity zones close to the main faults suggest the presence of hydrothermal activity and fluid circulation that could enhance flank instability. Our results provide new findings about the geometry of the unstable Etna flank and its relation to faults and subsurface structures.
    Beschreibung: This paper presents a magnetotelluric (MT) survey of the unstable eastern flank of Mt. Etna. We take thirty soundings along two profiles oriented in the N-S and NW-SE directions, and from these data recover two 2D resistivity models of the subsurface. Both models reveal three major layers in a resistive-conductive-resistive sequence, the deepest extending to 14 km bsl. The shallow layer corresponds to the volcanic cover, and the intermediate conductive layer corresponds to underlying sediments segmented by faults. These two electrical units are cut by E-W-striking faults. The third layer (basement) is interpreted as mainly pertinent to the Apennine-Maghrebian Chain associated with SW-NE-striking regional faults. The detailed shapes of the resistivity profiles clearly show that the NE Rift is shallow-rooted ( 0–1 km bsl), thus presumably fed by lateral dikes from the central volcano conduit. The NW-SE profile suggests by a series of listric faults reaching up to 3 km bsl, then becoming almost horizontal. Toward the SE, the resistive basement dramatically dips (from 3 km to 10 km bsl), in correspondence with the Timpe Fault System. Several high-conductivity zones close to the main faults suggest the presence of hydrothermal activity and fluid circulation that could enhance flank instability. Our results provide new findings about the geometry of the unstable Etna flank and its relation to faults and subsurface structures.
    Beschreibung: Published
    Beschreibung: B03216
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Etna ; magnetotelluric ; flank instability ; volcano ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.05. Geomagnetism::04.05.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
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    Spatial vent opening probability map of Etna volcano (Sicily, Italy) (2012)
    Springer Berlin Heidelberg
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We produce a spatial probability map of vent opening (susceptibility map) at Etna, using a statistical analysis of structural features of flank eruptions of the last 2 ky. We exploit a detailed knowledge of the volcano structures, including the modalities of shallow magma transfer deriving from dike and dike-fed fissure eruptions analysis on historical eruptions. Assuming the location of future vents will have the same causal factors as the past eruptions, we converted the geological and structural data in distinct and weighted probability density functions, which were included in a non-homogeneous Poisson process to obtain the susceptibility map. The highest probability of new eruptive vents opening falls within a N-S aligned area passing through the Summit Craters down to about 2,000 ma.s.l. on the southern flank. Other zones of high probability follow the North-East, East-North-East, West, and South Rifts, the latter reaching low altitudes (∼400 m). Less susceptible areas are found around the faults cutting the upper portions of Etna, including the western portion of the Pernicana fault and the northern extent of the Ragalna fault. This structuralbased susceptibility map is a crucial step in forecasting lava flow hazards at Etna, providing a support tool for decision makers.
    Beschreibung: This study was performed with the financial support from the V3-LAVA project (DPC-INGV 2007–2009 contract).
    Beschreibung: Published
    Beschreibung: 2083–2094
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Flank eruption ; Dike ; Volcano structure ; Susceptibility map ; Spatial clustering ; Back analysis ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
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    How do volcanic rift zones relate to flank instability? Evidence from collapsing rifts at Etna (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Volcanic rift zones, characterized by repeated dike emplacements, are expected to delimit the upper portion of unstable flanks at basaltic edifices. We use nearly two decades of InSAR observations excluding wintertime acquisitions, to analyze the relationships between rift zones, dike emplacement and flank instability at Etna. The results highlight a general eastward shift of the volcano summit, including the northeast and south rifts. This steadystate eastward movement (1-2 cm/yr) is interrupted or even reversed during transient dike injections. Detailed analysis of the northeast rift shows that only during phases of dike injection, as in 2002, does the rift transiently becomes the upper border of the unstable flank. The flank's steady-state eastward movement is inferred to result from the interplay between magmatic activity, asymmetric topographic unbuttressing, and east-dipping detachment geometry at its base. This study documents the first evidence of steady-state volcano rift instability interrupted by transient dike injection at basaltic edifices.
    Beschreibung: Partially funded by INGV and the Italian DPC (DPC-INGV project V4 “Flank”). ERS and ENVISAT SAR data were provided by ESA through the Cat-1 project no. 4532 and the GEO Supersite initiative. The DEM was obtained from the SRTM archive. ERS-1/2 orbits are courtesy of the TU-Delft, The Netherlands. SAR data processing has been done at IREACNR, partially carried out under contract “Volcanic Risk System (SRV)” funded by the Italian Space Agency (ASI).
    Beschreibung: Published
    Beschreibung: L20311
    Beschreibung: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): flank instability ; rift zones ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 30
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    Active extension in Val d’Agri area, Southern Apennines, Italy: implications for the geometry of the seismogenic belt. (2012)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: Integration of geologic, geomorphologic and seismologic data sets is used to reconstruct the recent tectonic evolution and active deformation pattern in the Val d’Agri area, located in the seismically active axial sector of the Southern Apennines (Italy). The western portion of the Apennines thrust belt has been affected by Pliocene–Quaternary extension during easterly roll-back and crustal delamination of the Adriatic slab. The bulk of Quaternary extension has been accommodated bySW-dipping oblique and normal faults,which have attained mature morphologic and structural features and, nowadays, separate mountain ranges from intermontane basins. However, in the present seismogenic belt, coseismic faulting locally occurs on NE-dipping structures, which might cut the inherited Pleistocene landscape. In theVal d’Agri basin, in spite of the large Early–Middle Pleistocene, displacement occurred on SW-dipping faults bordering its eastern flank, our investigations show that the recent basin evolution has been controlled by a NE-dipping fault system (Monti della Maddalena fault system, MMFS). This fault system cuts across the Monti della Maddalena range, west of the Agri valley and has not yet created an evident tectonic landscape. Notwithstanding, fault motion since the Middle Pleistocene might explain geomorphologic and hydrographic anomalies of the Agri river and its valley, where fault-controlled subsidence has captured the river course and produced an aggrading plain within a regional uplift context. Recent and ongoing motion is documented by fault scarplets in loose deposits, 14C ages of palaeosols and the spatial relation with low to moderate instrumental seismicity. Results from fault kinematic analysis are compatible with fault-plane solutions of local and regional seismic events, and indicate ∼NE–SW oriented extension. Recognition of the MMFS as a potential seismogenic fault increases the longitudinal extent of the NE-dipping, morphologically immature seismic sources in the Southern Apennines and argues against the range-bounding fault model for active extension in the region. The regional size of the NE-dipping seismogenic belt may result from impingement of a mantle wedge beneath the Apenninic chain and possibly track the external front of crustal delamination.
    Beschreibung: Published
    Beschreibung: 591-609
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): active tectonics ; crustal deformation ; earthquakes ; geomorphology ; normal faulting ; Southern Italy ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
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  • 31
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    Statistical analysis of the volcano seismicity during the 2007 crisis (2012)
    AGU
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We analyze the volcano seismicity recorded during the pre‐ and co‐eruptive regimes of the 2007 effusive crisis at Stromboli volcano (Italy). Data‐set is composed of the continuous recordings of a three‐component broad‐band seismometer and of a Sacks‐ Evertson strainmeter. Starting from the characterization of the non effusive phase as a stationary state of equilibrium, we investigate the effusive phase as a non‐equilibrium state. A statistical analysis reveals that the explosion occurrence is always driven by a nearly Poissonian process, as for the standard activity, even during the effusive phase, with the only difference in shortening the inter‐times. Explosion‐quake amplitudes are lognormally distributed until the effusive phase, becoming then broader. This indicates that many scales are involved. A slightly different process can be advocated for the swarms of the explosions occurring during the effusive phase. This suggests that the dynamics of the exsolution and/or aggregation of the gas slugs should differ from the nucleation mechanism responsible of the standard Strombolian activity. The pre‐eruptive regime is characterized by a very long deformative signal that appears as a transient oscillating signal with a period of about three days that modulates the explosion amplitudes. In a conceptual vibrating cavities model, it is related to a chocking phenomenon induced by magma injection, which in turn leads to the effusion.
    Beschreibung: Published
    Beschreibung: B09312
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Volcanic tremor ; Stromboli ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
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    Source mechanism of long-period events recorded by a high-density seismic network during the 2008 eruption on Mount Etna (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: One hundred twenty-nine long-period (LP) events, divided into two families of similar events, were recorded by the 50 stations deployed on Mount Etna in the second half of June 2008. During this period lava was flowing from a lateral fracture after a summit Strombolian eruption. In order to understand the mechanisms of these events, we perform moment tensor inversions. Inversions are initially kept unconstrained to estimate the most likely mechanism. Numerical tests show that unconstrained inversion leads to reliable moment tensor solutions because of the close proximity of numerous stations to the source positions. However, single forces cannot be accurately determined as they are very sensitive to uncertainties in the velocity model. Constrained inversions for a crack, a pipe or an explosion then allow us to accurately determine the structural orientations of the source mechanisms. Both numerical tests and LP event inversions emphasise the importance of using stations located as close as possible to the source. Inversions for both families show mechanisms with a strong volumetric component. These events are most likely generated by cracks striking SW–NE for both families and dipping 70° SE (family 1) and 50° NW (family 2). For family 1 events, the crack geometry is nearly orthogonal to the dikelike structure along which events are located, while for family 2 the location gave two pipelike bodies that belong to the same plane as the crack mechanism. The orientations of the cracks are consistent with local tectonics, which shows a SW–NE weakness direction. The LP events appear to be a response to the lava fountain occurring on 10 May 2008 as opposed to the flank lava flow.
    Beschreibung: Published
    Beschreibung: B01304
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Etna Volcano ; long-period events ; source mechanism ; location ; plumbing systems ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 33
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    Splitting parameter yield (SPY): A program for semiautomatic analysis of shear wave splitting (2012)
    Elsevier
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: SPY is a Matlab algorithm that analyzes seismic waveforms in a semiautomatic way, providing estimates of the two observables of the anisotropy: the shear-wave splitting parameters. We chose to exploit those computational processes that require less intervention by the user, gaining objectivity and reliability as a result. The algorithm joins the covariance matrix and the cross-correlation techniques, and all the computation steps are interspersed by several automatic checks intended to verify the reliability of the yields. The resulting semiautomation generates two new advantages in the field of anisotropy studies: handling a huge amount of data at the same time, and comparing different yields. From this perspective, SPY has been developed in the Matlab environment, which is widespread, versatile, and user-friendly. Our intention is to provide the scientific community with a new monitoring tool for tracking the temporal variations of the crustal stress field.
    Beschreibung: Published
    Beschreibung: 138-145
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Crustal anisotropy ; Waveform analysis ; Seismic monitoring ; Stress field ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 34
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    The failed eruption of Mt. Etna in December 2005: evidence from volcanic tremor analyses (2014)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Strong changes in seismic radiation, comparable to those preceding and/or accompanying eruptive activity in recent years, were recorded at Mt. Etna volcano, Italy, from November 2005 to January 2006. The amplitude of volcanic tremor peaked in mid-December 2005 after a continuous, slow increase from August 2005 onwards, during which neither effusive nor paroxysmal activity was observed by volcanologists and alpine guides. During this time span, the centroid locations of volcanic tremor moved towards the surface, more and more clustered below the summit craters. The application of pattern classification analysis based on Self-Organizing Maps and fuzzy clustering to volcanic tremor data highlighted variations in the frequency domain as well. These changes were temporally associated with ground deformation variations, as indicative of a mild inflation of the summit of the volcano, and with a conspicuous increase in the SO2 plume-flux emission. Overall, we interpret this evidence as the result of recharging of the volcanic feeder at depth (〉 3 km below sea level) during which magma did not reach the shallow plumbing system.
    Beschreibung: Published
    Beschreibung: 4989–5005
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: JCR Journal
    Beschreibung: embargoed_20140606
    Schlagwort(e): time series analysis ; volcano seismology ; volcano monitoring ; neural network and fuzzy logic ; seismic tomography ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
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    Probabilistic modeling of future volcanic eruptions at Mount Etna (2014)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The statistical analysis of volcanic activity at Mt Etna was conducted with the twofold aim of (1) constructing a probability map for vent opening of future flank eruptions and (2) forecasting the expected number of eruptive events at the summit craters. The spatiotemporal map of new vent opening at Etna volcano is based on the analysis of spatial locations and frequency of flank eruptions starting from 1610. Thanks to the completeness and accuracy of historical data over the last four centuries, we examined in detail the spatial and temporal distribution of flank eruptions showing that effusive events follow a nonhomogenous Poisson process with space-time varying intensities. After demonstrating the spatial nonhomogeneity and the temporal nonstationarity of flank eruptions at Etna, we calculated the recurrence rates (events expected per unit area per unit time) and produced different spatiotemporal probability maps of new vent opening in the next 1, 10 and 50 years. These probabilistic maps have an immediate use in evaluating the future timing and areas of Etna prone to volcanic hazards. Finally, the results of the analysis of the persistent summit activity during the last 110 years indicate that the hazard rate for eruptive events is not constant with time, differs for each summit crater of Mt Etna, highlighting a general increase in the eruptive frequency starting from the middle of last century and particularly from 1971, when the SE crater was formed.
    Beschreibung: This work was developed in the frame of the TecnoLab, the Laboratory for the Technological Advance in Volcano Geophysics organized by INGV-CT, DIEES-UNICT, and DMI-UNICT.
    Beschreibung: Published
    Beschreibung: 1925-1935
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: 3V. Dinamiche e scenari eruttivi
    Beschreibung: 4V. Vulcani e ambiente
    Beschreibung: 3IT. Calcolo scientifico e sistemi informatici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Etna ; probabilistic modeling ; eruption ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
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    Seismo-tectonic behavior of the Pernicana Fault System (Mt Etna): A gauge for volcano flank instability? (2014)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Flank instability at basaltic volcanoes is often related to repeated dike intrusions along rift zones and accompanied by surface fracturing and seismicity. These processes have been mostly studied during specific events, and the lack of longer-term observations hinders their better understanding. Here we analyze ~20 years of deformation of the Pernicana Fault System (PFS), the key structure controlling the instability of the eastern flank of Mt. Etna. We exploit East-West and vertical components of mean deformation velocity, as well as corresponding time series, computed from ERS/ENVISAT (1992–2010) and COSMO-SkyMed (2009–2011) satellite radar sensors via Synthetic Aperture Radar Interferometry techniques. We then integrate and compare this information with field, seismic, and leveling data, collected between 1980 and 2012. We observe transient displacements accompanied by seismicity, overprinted on a long-term background eastward motion (~2 cm/yr). In the last decades, these transient events were preceded by a constant amount of accumulated strain near the PFS. The time of strain accumulation varies between a few years and a few decades, also depending on magma emplacement within the nearby North East Rift, which may increase the strain along the PFS. These results suggest that the amount of deformation near the PFS may be used as a gauge to forecast the occurrence of instability transients on the eastern flank of Etna. In this context, the PFS may provide an ideal, small-scale structure to test the relations between strain accumulation, stress loading, and seismic energy release.
    Beschreibung: This work has been partially supported by the Italian Space Agency (ASI) within the SAR4Volcanoes project, agreement I/ 034/11/0.
    Beschreibung: Published
    Beschreibung: 4398-4409
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: 5T. Sorveglianza sismica e operatività post-terremoto
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: 3V. Dinamiche e scenari eruttivi
    Beschreibung: 4V. Vulcani e ambiente
    Beschreibung: 6A. Monitoraggio ambientale, sicurezza e territorio
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Volcano flank instability ; Pernicana fault ; Etna ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
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    The coupling between very long period seismic events, volcanic tremor, and degassing rates at Mount Etna volcano (2014)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: From December 2005 to January 2006, an anomalous degassing episode was observed at Mount Etna, well-correlated with an increase in volcanic tremor, and in the almost complete absence of eruptive activity. In the same period, more than 10,000 very long period (VLP) events were detected. Through moment tensor inversion analyses of the VLP pulses, we obtained quantitative estimates of the volumetric variations associated with these events. This allowed a quantitative investigation of the relationship between VLP seismic activity, volcanic tremor, and gas emission rate at Mount Etna. We found a statistically significant positive correlation between SO2 gas flux and volcanic tremor, suggesting that tremor amplitude can be used as a first-order proxy for the background degassing activity of the volcano. VLP volumetric changes and SO2 gas flux are correlated only for the last part of our observations, following a slight change in the VLP source depth. We calculate that the gas associated with VLP signal genesis contributed less than 5% of the total gas emission. The existence of a linear correlation between VLP and degassing activities indicates a general relationship between these two processes. The effectiveness of such coupling appears to depend upon the particular location of the VLP source, suggesting that conduit geometry might play a significant role in the VLP-generating process. These results are the first report on Mount Etna of a quantitative relationship between the amounts of gas emissions directly estimated through instrumental flux measurements and the quantities of gas mass inferred in the VLP source inversion.
    Beschreibung: Published
    Beschreibung: 4910-4921
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Very Long Period seismicity ; UV scanners network ; Etna Volcano ; volcano monitoring ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
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    A statistical study of the Stromboli volcano explosion quakes before and during 2002-2003 eruptive crisis (2012)
    AGU
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We study the seismic wavefield and the statistical properties of the Stromboli volcano explosions preceding and during the 2002–2003 crisis. We analyze the recordings of a three‐component seismometer operating since 23 May 2002 to 30 January 2003, including the first 34 days of the crisis. Before the crisis, we recognize three bell‐shaped classes of spectra with maxima falling in the range 1–5 Hz. Spectral content has two main changes, the most prominent one occurring at the crisis onset when the frequency peak at ∼0.3 Hz increases in amplitude. Independent component analysis extracts three time‐stable independent oscillations that peaked at 1.1, 1.8, and 2.5 Hz, with radial and shallow polarization indicating a stable source mechanism. Energy of the explosions is lognormally distributed, except during a 2 month time interval before the crisis when it also shows a higher mean value. The interoccurrence time distributions display an homogeneous Poissonian behavior with a mean intertime of 250 s, without changes at the crisis onset. Only swarms of explosions are not ruled by a Poisson process and display higher occurrence rates and higher energies. Finally, we depict a scheme of the crisis. A modification of the equilibrium is induced by rising magma that produces a change in the boundary conditions of the plumbing system. The escape from the equilibrium produces, at first, variations in the usual statistics of the explosions, then it leads to the lava effusion and to a pressure drop in the plumbing system that induces a deep gas slug nucleation and the excitation of low frequencies.
    Beschreibung: Published
    Beschreibung: B04303
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Stromboli volcano, explosion quakes, 2002-2003 eruption ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
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    Slug Flow: Modeling in a Conduit and Associated Elastic Radiation (2012)
    Springer
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: Among the eruptive styles, the Strombolian activity is one of the more easy to study because of its repetitive behavior. For this reason large amount of data can be comfortably collected. Strombolian volcanoes are like natural laborato- ries repeating the same experiment (individual explosions) many times each day. The development of quantitative models of eruptive dynamics is driven by the comparison of experimental ob- servations and synthetic data obtained through mathemat- ical, numerical or analogue modeling. Since Strombolian activity offers a profuse amount of interesting seismic signals, during the last decades there has been growing attention on seismological techniques aimed at retrieving the conduit geometry and the eruption dynamics from the seismological recordings. One of these techniques, the source function inversion, is able to re- trieve a summary of the forces acting on the volcanic con- duit during the VLP event generation [5]. The comparison of observed source functions with synthetic ones, obtained through numerical modeling, allow us to put constraints on the proposed models. Quantitative models, able to fit seismological observa- tions, are a powerful tool for interpreting seismic record- ings and therefor the seismological monitoring of active volcanoes.
    Beschreibung: Published
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: restricted
    Schlagwort(e): Strombolian activity ; Slug flow ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book chapter
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  • 40
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    Pattern recognition of volcanic tremor data on Mt. Etna (Italy) with KKAnalysis — A software program for unsupervised classification (2012)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Continuous seismic monitoring plays a key role in the surveillance of the Mt. Etna volcano. Besides earthquakes, which often herald eruptive episodes, the persistent background signal, known as volcanic tremor, provides important information on the volcano status. Changes in the regimes of activity are usually concurrent with variations in tremor characteristics. As continuous recording leads rapidly to the accumulation of large amounts of data, parameter extraction and automated processing become crucial. We propose techniques of unsupervised classification and present a software, named KKAnalysis, developed for this purpose. Essentials of KKAnalysis are demonstrated on tremor data recorded on Mt. Etna during various states of volcanic activity encountered in 2007 and 2008. KKAnalysis is based on MATLAB and combines various unsupervised pattern recognition techniques, in particular self-organizing maps (SOM) and cluster analysis. An early software version was successfully applied to seismic signals recorded on Mt. Etna during the eruption in 2001. Since each situation may require different configurations, we designed KKAnalysis with a specific GUI allowing users to easily modify parameters. All results are given graphically, in screen plots and metafiles (MATLAB and TIF format), as well as in alphanumeric form. The synoptic visualization of results from SOM and cluster analysis facilitates an immediate inspection. The potential of this representation is demonstrated by focusing on data recorded during a flank eruption on May 13, 2008. Changes of tremor characteristics can be clearly identified at a very early stage, well before enhanced volcanic activity becomes visible in the time series. At the same time, data reduction to less than 1% of the original amount is achieved, which facilitates interpretation and storage of the essential information. Running the program in a typical configuration requires computing time less than 1 min, allowing an on-line application for early warning purposes at INGV–Sezione di Catania
    Beschreibung: Published
    Beschreibung: 953-961
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 5.6. TTC - Attività di Sala Operativa
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Self-Organizing Map ; Cluster Analysis ; K-means ; Fuzzy C-means ; Volcano Seismology ; Volcano Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 41
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    Multiparametric Approach in Investigating Volcano-Hydrothermal Systems: the Case Study of Vulcano (Aeolian Islands, Italy) (2012)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Seismic activity, ground deformation, and soil and fumarole temperatures acquired during 2004–2007 at Vulcano (Aeolian Islands) are analysed and the time relations among the different time series are discussed. Changes in temperature of fumarolic gases took place during four ‘‘anomalous’’ periods (November 2004–March 2005; October 2005–February 2006; August–October 2006; July–December 2007) at the same time as an increasing number of volcano-seismic events. In particular, the temperatures at high temperature vents and at steam heated soil ranged in time from 180 to 440 C and from 20 to 90 C, respectively. The maximum daily number of volcano-seismic events was 57, reached during the second anomalous period. This seismicity, characterised by focal depth generally lower than 1 km below sea level (b.s.l.) and composed of different kinds of events associated to both resonance and shear failure processes, is related to the shallow dynamics of the hydrothermal system. During the analysed period, very few volcano-tectonic earthquakes took place and tilt recordings showed no sharp or important changes. In light of such observations, the increases in both temperature and volcano-seismic events number were associated to increases in the release of gas from a deep and stable magma body, without magma intrusions within the shallow hydrothermal system. Indeed, a greater release of gas from depth leads to increased fluid circulation, that can promote increases in volcano-seismic events number by both fracturing processes and resonance and vibration in cracks and conduits. The different trends observed in the measured geochemical and geophysical series during the anomalous periods can be due to either time changes in the medium permeability or a changing speed of gas release from a deep magma body. Finally, all the observed variations, together with the changing temporal distribution of the different seismic event kinds, suggest that the hydrothermal system at Vulcano can be considered unsteady and dynamic.
    Beschreibung: Published
    Beschreibung: 167–182
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Volcano seismolog ; soil and fumarole temperatures ; tilt data ; hydrothermal system ; Vulcano Island ; volcanic unrest ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 42
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    Inferences on the source of long-period seismicity at Campi Flegrei from polarization analysis and reconstruction of the asymptotic dynamics (2012)
    Springer Berlin Heidelberg
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In the present paper, we analyse long-period (LP) events and seismic noise recorded at Campi Flegrei during the uplift episode of 2004–2006. The results of a detailed polarization analysis indicate that the large number of LPs detected during the seismic crisis were accompanied by a sustained activity consisting of very low-energy volcanic signals. These weak volcanic signals, which are usually absent in ambient noise recorded in the studied area, and LP events have similar properties, namely they are radially polarized towards the same LP source. The large dataset analysed allows us to study the statistics of the polarization, leading to the extraction of the average properties of the volcanic signals. An estimate of the complexity of the system can be provided by the degrees of freedom necessary to describe the asymptotic dynamics in a reconstructed phase space. This analysis shows that both LPs and low-energy signals can be described by a low-dimensional dynamical system, while ambient noise unrelated to volcanic activity is higher dimensional. Based on these observations, we interpret the phenomena observed during the seismic crisis in the framework of the theory of self-oscillating systems, in which LPs and low-energy signals represent self-oscillations generated by a persistent hydrothermal source.
    Beschreibung: Published
    Beschreibung: 1537-1551
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Campi Flegrei, Long-period events, Self-sustained oscillations ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
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    Morphometric analysis in the offshore of the southern Taranto Gulf: unveiling the structures controlling the Late Pleistocene-Holocene bathymetric evolution (2012)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The present study is focused on a morphometric analysis of high resolution multibeam data (10m, 5m and, locally, 2m resolution), that were acquired during the oceanographic TEATIOCA 2011 campaign along a sector of the Ionian margin of northern Calabria. The integration of morphometric analysis with sparker and chirp data allowed to unveil basic but robust information about: 1. hierarchy of the fault systems controlling the bathymetric evolution; 2. the interplay between tectonic and erosional processes in sea-floor modeling; 3. uplift rates; 4. tilting processes.
    Beschreibung: Published
    Beschreibung: Arcavacata di Rende (CS)
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: open
    Schlagwort(e): fault modeling ; erosional marine terraces ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Extended abstract
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  • 44
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    Deformed Pleistocene marine terraces along the Ionian sea margin of southern Italy: Unveiling blind fault-related folds contribution to coastal uplift (2012)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Morphotectonic analysis and fault numeric modeling of uplifted marine terraces along the southern half of the Taranto Gulf , between the Sibari and San Nicola plains (Fig. 1), allow us to place quantitative constraints on Middle Pleistocene-Holocene deformation in the Southern Apennines.
    Beschreibung: Published
    Beschreibung: Arcavacata di Rende (CS)
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: open
    Schlagwort(e): Marine terraces ; Regional uplift ; Fault propagation folds ; Fault modeling ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Extended abstract
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  • 45
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    Multiple resolution seismic attenuation imaging at Mt. Vesuvius (2010)
    Elsevier
    Details
    Publikationsdatum: 2019-03-05
    Beschreibung: A three-dimensional S wave attenuation tomography of Mt. Vesuvius has been obtained with multiple measurements of coda-normalized S-wave spectra of local small magnitude earthquakes.We used 6609 waveforms, relative to 826 volcano-tectonic earthquakes, located close to the crater axis in a depth range between 1 and 4 km (below the sea level), recorded at seven 3-component digital seismic stations. We adopted a two-point ray-tracing; rays were traced in an high resolution 3-D velocity model. The spatial resolution achieved in the attenuation tomography is comparable with that of the velocity tomography (we resolve 300m side cubic cells). We statistically tested that the results are almost independent from the radiation pattern. We also applied an improvement of the ordinary spectral-slope method to both P- and S-waves, assuming that the differences between the theoretical and the experimental high frequency spectral-slope are only due to the attenuation effects. Consequently we could check the codanormalization method also comparing the S attenuation image with the P attenuation image. The images were obtained inverting the spectral data with a multiple resolution approach. Results have shown the general coincidence of low attenuation with high velocity zones. The joint interpretation of velocity and attenuation images allows us to interpret the low attenuation zone intruding toward the surface until a depth of 500m below the sea level as related to the residual part of solidified magma from the last eruption. In the depth range between −700 and −2300 images are consistent with the presence of multiple acquifer layers. No evidence of magma patches greater than the minimum cell dimension (300m) has been found. A shallow P wave attenuation anomaly (beneath the southern flank of the volcano) is consitent with the presence of gas saturated rocks. The zone characterized by the maximum seismic energy release cohincides with a high attenuation and low velocity volume, interpreted as a cracked medium.
    Beschreibung: Published
    Beschreibung: 17–32
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Attenuation tomography ; Mt. Vesuvius ; Coda normalization method ; Spectral slope ; Multi resolution inversion ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 46
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    Correlation of welded ignimbrites on Pantelleria (Strait of Sicily) using paleomagnetism (2012)
    Springer Berlin Heidelberg
    Details
    Publikationsdatum: 2017-10-06
    Beschreibung: Although the oldest volcanic rocks exposed at Pantelleria (Strait of Sicily) are older than 300 ka, most of the island is covered by the 45–50 ka Green Tuff ignimbrite, thought to be related to the Cinque Denti caldera, and younger lavas and scoria cones. Pre-50 ka rocks (predominantly rheomorphic ignimbrites) are exposed at isolated sea cliffs, and their stratigraphy and chronology are not completely resolved. Based on volcanic stratigraphy and K/Ar dating, it has been proposed that the older La Vecchia caldera is related to ignimbrite Q (114 ka), and that ignimbrites F, D, and Z (106, 94, and 79 ka, respectively) were erupted after caldera formation. We report here the paleomagnetic directions obtained from 23 sites in ignimbrite P (133 ka) and four younger ignimbrites, and from an uncorrelated (and loosely dated) welded lithic breccia thought to record a caldera-forming eruption. The paleosecular variation of the geomagnetic field recorded by ignimbrites is used as correlative tool, with an estimated time resolution in the order of 100 years. We find that ignimbrites D and Z correspond, in good agreement with recent Ar/Ar ages constraining the D/Z eruption to 87 ka. The welded lithic breccia correlates with a thinner breccia lying just below ignimbrite P at another locality, implying that collapse of the La Vecchia caldera took place at ~130–160 ka. This caldera was subsequently buried by ignimbrites P, Q, F, and D/Z. Paleomagnetic data also show that the northern caldera margin underwent a ~10° west–northwest (outwards) tilting after emplacement of ignimbrite P, possibly recording magma resurgence in the crust.
    Beschreibung: Published
    Beschreibung: 341-357
    Beschreibung: 1V. Storia eruttiva
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Pantelleria ; Ignimbrite ; Caldera formation ; Paleomagnetism ; Paleosecular variation of the geomagnetic field ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.05. Geomagnetism::04.05.99. General or miscellaneous ; 04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals ; 04. Solid Earth::04.05. Geomagnetism::04.05.03. Global and regional models ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 47
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    Unbekannt
    Time-space variation of volcano-seismic events at La Fossa (Vulcano, Aeolian Islands, Italy): new insights into seismic sources in a hydrothermal system (2010)
    Springer
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: We investigated the relationship between volcano-seismic events, recorded at La Fossa crater of Vulcano (Aeolian Islands, Italy) during 2004-2006, and the dynamics of the hydrothermal system. During the period of study, three episodes of increasing numbers of volcano-seismic events took place at the same time as geothermal and geochemical anomalies were observed. These geothermal and geochemical anomalies have been interpreted as resulting from an increasing deep magmatic component of the hydrothermal fluids. Three classes of seismic events (long period, high frequency and monochromatic events), characterised by different spectral content and various similarity of the waveforms, have been recognised. These events, clustered mainly below La Fossa crater area at depths of 0.5–1.1 km b.s.l., were space-distributed according to the classes. Based on their features, we can infer that such events at Vulcano are related to two different source mechanisms: (1) fracturing processes of rocks and (2) resonance of cracks (or conduits) filled with hydrothermal fluid. In the light of these source mechanisms, the increase in the number of events, at the same time as geochemical and geothermal anomalies were observed, was interpreted as the result of an increasing magmatic component of the hydrothermal fluids, implying an increase of their flux. Indeed, such variation caused an increase of both the pore pressure within the rocks of the volcanic system and the amount of ascending fluids. Increased pore pressures gave rise to fracturing processes, while the increased fluid flux favoured resonance and vibration processes in cracks and conduits. Finally, a gradual temporal variation of the waveform of the hybrid events (one of the subclasses of long period events) was observed, likely caused by heating and drying of the hydrothermal system.
    Beschreibung: Published
    Beschreibung: 803-816
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Volcano seismology ; Vulcano Island ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 48
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    Unbekannt
    Fault plane orientations of microearthquakes at Mt. Etna from theinversion of P-wave rise times (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: A crucial point in the analysis of tectonic earthquakes occurring in a volcanic area is the inference of the orientation of the structures along which the ruptures occur. These structures represent zones of weakness which could favor the migration of melt toward the surface and the assessment of their geometry is a fundamental step toward efficient evaluation of volcanic risk. We analyzed a high-quality dataset of 171 lowmagnitude, tectonic earthquakes that occurred at Mt. Etna during the 2002–2003 eruption. We applied a recently developed technique aimed at inferring the source parameters (source size, dip and strike fault) and the intrinsic quality factor Qp of P waves from the inversion of rise times. The technique is based on numerically calibrated relationships among the rise time of first P waves and the source parameters for a circular crack rupturing at a constant velocity. For the most of the events the directivity source effect did not allow us to constrain the fault plane orientation. For a subset of 45 events with well constrained focal mechanisms we were able to constrain the “true” fault plane orientation. The level of resolution of the fault planes was assessed through a non linear analysis based on the random deviates technique. The significance of the retrieved fault plane solutions and the fit of the assumed source model to data were assessed through a χ-square test. Most of the retrieved fault plane solutions agree with the geometrical trend of known surface faults. The inferred source parameters and Qp are in agreement with the results of previous studies
    Beschreibung: Published
    Beschreibung: 247-256
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): rise time ; directivity ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 49
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    Unbekannt
    Geometric and Kinematic modeling of the thrust fronts in the Montello-Cansiglio area from geologic and geodetic data (Eastern Southalpine Chain, NE Italy) (2010)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2022-04-29
    Beschreibung: Questo lavoro è dedicato allo studio delle geometrie e dei ratei di deformazione di breve e medio termine delle strutture compressive attive facenti parte dei fronti esterni della Catena Sudalpina, nel settore dell’anticlinale del Montello. Il metodo adottato utilizza informazioni derivate dall’analisi di una linea geodetica di primo ordine dell’IGM, combinate con osservazioni geofisiche, geologiche e geomorfologiche di superficie e di sottosuolo. La linea geodetica presa in esame mostra lungo alcuni suoi segmenti dei movimenti verticali relativi, positivi rispetto ai segmenti adiacenti (maggiori sollevamenti). Questi segnali geodetici, ottenuti dal confronto delle quote dei capisaldi misurate durante due distinte campagne separate da un intervallo di tempo di circa 50 anni, avvengono in corripondenza dell’attraversamento di faglie cieche e sono stati quindi interpretati come dovuti all’attività di queste strutture sepolte. Per l’interpretazione, è stata costruita una sezione geologica che segue la traccia della linea di livellazione, ed è stato quindi modelizzato il segnale geodetico adottando un metodo diretto. Nel modello, le geometrie di partenza delle faglie sono state prese dalla sezione geologica, e sono state poi modificate per riprodurre il segnale geodetico. Una volta fissate le geometrie delle faglie, gli uplift rate sono stati convertiti in slip e shortening rate e comparati con: 1- i ratei di medio e lungo termine derivati dalle osservazioni geologiche e geomorfologiche per evidenziare eventuali cambiamenti nel tempo; e 2- con i tassi di convergenza GPS per studiare la partizione delle deformazione tra i diversi fronti. Infine sono state usate relazioni analitiche ed empiriche per stimare la massima magnitudo e i tempi di ricorrenza dei potenziali futuri terremoti.
    Beschreibung: Published
    Beschreibung: Udine
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: open
    Schlagwort(e): Montello Anticline ; Eastern Southalpine Chain ; slip rates ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Extended abstract
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  • 50
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    Unbekannt
    A case study comparing landscape metrics to geologic and seismic data from the Ischia Island (Southern Italy) (2010)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In this paper, a high-resolution digital elevation model (DEM) of the Ischia Island has been created, and a digital terrain analysis has been carried out to identify of morphostructural elements of this landscape. Ischia is an active volcano located in the Western sector of the Gulf of Naples that is characterized by historical and recent volcano-tectonic activity. The local kinematics is unclear, and so identification of tectonic lineaments might elucidate recent tectonic processes. We identify morphostructural features using geomorphic parameters derived from analysis of the high-resolution DEM. Successively, the comparison with known geologic features provides validation of the extracted morphotectonic data.We found that one of the main directions of the morphostructural lineaments extracted is consistent with the regional NE–SW extensional stress field; moreover, the lineaments on the northern flank of Mt. Epomeo are strictly correlated with the mapped faults that have a history of strong and moderate earthquakes. The technique implemented for this study area allowed us to identify new original morphostructural lineaments in a reproducible way that may be useful for investigating various landscapes where field survey is not possible. Indeed, the extracted lineaments represent potential active faults near the northern coast of the Ischia Island, where both seismicity and intense urbanization delineate a high seismic risk.
    Beschreibung: Published
    Beschreibung: 73-82
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: N/A or not JCR
    Beschreibung: reserved
    Schlagwort(e): Digital elevation model . Morphostructural lineaments . Tectonic geomorphology. Residual topographic surface ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 51
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    Unbekannt
    Late Matuyama climate forcing on sedimentation at the margin of the southern Alps (Italy) (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The Pleistocene history of climate control on sedimentation in the Southern Alps-Po Plain system, northern Italy, was reconstructed using an integrated magnetostratigraphic, palynological, and petrographical approach on a 47-m-deep core. The core mainly consists of lacustrine sediments pertaining to the Bagaggera sequence, deposited at the foothills of the Southern Alps during the late Matuyama subchron (0.99-0.78 Ma). At that time, climate worsened globally and locally it caused the progradation of an alluvial fan unit onto the nearby Po Plain, triggering lake formation by damming of a tributary valley. These new data are used in conjunction with data from the literature to highlight and track the effects of climate forcing on sedimentation during the late Matuyama subchron in different orographic and geodynamic settings of the Southern Alps-Po Plain system as part of the greater Alpine area. We found that the episodes of alluvial fan and braidplam progradation observed in the southern foreland of the Alps during the late Matuyama global cooling seem broadly synchronous with the deposition of most of the so-called Gunz and Alterer Deckenschotter deposits in the northern forelands of the Alps as well as with the first major waxing of the Alpine valley glaciers, possibly around the Marine Isotope Stage 22 (~0.87 Ma).
    Beschreibung: Regione Lombardia, IREALP
    Beschreibung: Published
    Beschreibung: 832–846
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Paleomagnetism ; Climate Change ; Early Pleistocene ; Italy ; Stratigraphy ; Petrography ; Palynology ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 52
    facet.materialart.
    Unbekannt
    Changes in the VLP seismic source during the 2007 Stromboli eruption (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Aim of this paper is to identify variations in Very-Long-Period (VLP) source associated with eruptive style changes at Stromboli volcano (Italy) and to retrieve information about the shallow plumbing system that sustains the eruptive activity. We have considered a dataset of 74493 VLP events recorded during the period from January through August 2007, when an effusive eruption occurred (February 27–April 2).We performed a polarization analysis of the entire dataset and divided the considered period into four sub-periods on the basis of polarization characteristics. We then located the events and selected a subset of these events by applying a location quality threshold. The high quality locations demonstrate that during the effusive eruption the VLP sources first moved downward and then moved southwestward. To retrieve information about the geometry of the structures where the source processes take place, we further consider a subset of events and estimate their source mechanisms by using a moment tensor source function (MTSF) inversion technique. Inversion of the waveforms of the VLP events that occurred on February 27 allows us to obtain information about the dynamics of different source centroids distributed along different portions of the shallow magmatic conduits. The structure defined by the locations and source mechanisms shows a greater complexity compared with previous studies and their time variations give an insight into the kinematics of the eruption.
    Beschreibung: Published
    Beschreibung: 162–171
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): stromboli ; very-long-period events ; seismic source mechanism ; volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 53
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    Unbekannt
    Distribution of volcanic earthquake recurrence intervals (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We analyze the distribution of volcanic earthquake recurrence intervals in the Vesuvio, Campi Flegrei, and Hawaii regions and compare it with tectonic recurrence rates in California. We find that the distribution behavior is similar for volcanic and tectonic seismic events. In both cases, the recurrence interval distributions collapse onto the same master curve if time is rescaled by the average occurrence rate. This implies that both phenomena have the same temporal organization, and it is possible to adopt for volcanic areas that the same occurrence models used for tectonic regions.
    Beschreibung: Published
    Beschreibung: B10309
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): volcanic earthquake ; recurrence intervals ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 54
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    Unbekannt
    Detachment depth revealed by rollover deformation: An integrated approach at Mount Etna (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Flank instability is common at volcanoes, even though the subsurface structures, including the depth to a detachment fault, remain poorly constrained. Here, we use a multidisciplinary approach, applicable to most volcanoes, to evaluate the detachment depth of the unstable NE flank of Mt. Etna. InSAR observations of Mount Etna during 1995–2008 show a trapdoor subsidence of the upper NE flank, with a maximum deformation against the NE Rift. The trapdoor tilt was highest in magnitude in 2002–2004, contemporaneous with the maximum rates of eastward slip along the east flank. We explain this deformation as due to a general eastward displacement of the flank, activating a rotational detachment and forming a rollover anticline, the head of which is against the NE Rift. Established 2D rollover construction models, constrained by morphological and structural data, suggest that the east‐dipping detachment below the upper NE flank lies at around 4 km below the surface. This depth is consistent with seismicity that clusters above 2–3 km below sea level. Therefore, the episodically unstable NE flank lies above an east‐dipping rotational detachment confined by the NE Rift and Pernicana Fault. Our approach, which combines short‐term (InSAR) and long‐term (geological) observations, constrains the 3D geometry and kinematics of part of the unstable flank of Etna and may be applicable and effective to understand the deeper structure of volcanoes undergoing flank instability or unrest.
    Beschreibung: This work was partially funded by INGV and the DPC‐INGV project “Flank”, and partially by the ASI (SRV project).
    Beschreibung: Published
    Beschreibung: L16304
    Beschreibung: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): flank instability ; fault ; InSAR ; Etna ; rollover ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 55
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    Unbekannt
    Messinian-Early Pliocene crustal shortening along the Tyrrhenian margin of Tuscany, Italy (2010)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2022-05-04
    Beschreibung: This paper illustrates the results of structural studies carried out in the western margin of Tuscany along a major crustal structure. Surface deformation of sediments filling different basins aligned on top of this major structure (from north to south: the Fine Basin, the Sassa–Guardistallo basin, the Rio Guardigiano area in the Lustignano basin) allow us to date its tectonic activity to the Messinian-Early Pliocene. In these areas, structures such as reverse and strike-slip faults and mesoscopic folds are widely developed. Structural analysis determined a compressive stress field with the σ1 oriented from E-W to NE-SW active from Messinian to Early Pliocene. At the southern end of this crustal structure, the Gavorrano antiform and the granitic pluton (radiometric age of granite ~4.4 Ma) coring this fold correlate with a thrust ramp anticline at depth, and thus constrain thrust activity to the Early Pliocene. These data document a Messinian–Early Pliocene compressive activity that contrasts with models invoking continuous extensional tectonics affecting the hinterland since the Late Oligocene-Middle Miocene in the frame of a back-arc-slab retreating process. The results presented therefore raise the question of which geodynamical model could account for such a complex structural evolution of Northern Apennines hinterland.
    Beschreibung: Published
    Beschreibung: 593-604
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Northern Apennines ; hinterland areas ; structural analysis ; pluton emplacement ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 56
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    Unbekannt
    Erosion of the continental lithosphere at the cusps of the Calabrian arc: Evidence fromSreceiver functions analysis (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2022-05-04
    Beschreibung: Mediterranean tectonics has been characterized by an irregular, complex temporal evolution with episodic rollback and retreat of the subducted plate followed by period of slow trench-migration. To provide insight into the geodynamics of the Calabrian arc, we image the characteristics and lithospheric structure of the convergent, Apulian and Hyblean forelands at the cusps of the arc. Specifically we investigate the crustal and lithospheric thicknesses using teleseismic S-to-p converted phases, applied to the Adria-Africa plate margin for the first time. We find that the Moho in the Apulian foreland is nearly flat at ∼30 km depth, consistent with previous P receiver functions results, and that the Hyblean crustal thickness is more complex, which can be understood in terms of the nature of the individual pieces of carbonate platform and pelagic sediments that make up the Hyblean platform. The lithospheric thicknesses range between 70–120 km beneath Apulia and 70–90 km beneath Sicily. The lithosphere of the forelands at each end of the Calabrian arc are continental in nature, buoyant compared to the subducting oceanic lithosphere and have previously been interpreted as mostly undeformed carbonate platforms. Our receiver function images also show evidence of lithospheric erosion and thinning close to Mt. Etna and Mt. Vulture, two volcanoes which have been associated with asthenospheric upwelling and mantle flow around of the sides the slab. We suggest that as the continental lithosphere resists being subducted it is being thermo-mechanically modified by toroidal flow around the edges of the subducting oceanic lithosphere of the Calabrian arc.
    Beschreibung: Published
    Beschreibung: L23301
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): continental lithosphere ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 57
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    Unbekannt
    New insights on the Holocene marine transgression in the Bahía Camarones (Chubut, Argentina) (2012)
    Società Geologica Italiana
    Details
    Publikationsdatum: 2022-06-10
    Beschreibung: The stratigraphic reconstruction of the northern sector of the Bahía Camarones (Chubut, Argentina) allowed to improve our understanding of the Holocene marine transgression in the area. The first phase of the maximum of the transgression, is interpreted as dominated by the high rate of eustatic rise of sea level until ca. 6-7 ka BP possibly associated to sedimentary starvation as suggested by fossil accumulation. After this first phase, the general trend indicates a progressive fall of the relative sea level after the Middle Holocene high stand as documented in other parts of south America Atlantic coast. Our data, coupled with the robust radiocarbon data set available for the area from literature, indicate three main local steps of coastal aggradation between ca. 6600 and 5400 yr BP (ca. 7000-5600 yr cal BP), ca. 3300 and 2000 yr BP (ca. 3100-1700 yr cal BP), and ca. 1300-500 yr BP (ca. 1000-300 yr cal BP). A significant age gap in coastal aggradation is present between ca. 5300 and 4400 yr BP (ca. 5600-4500 yr cal BP), and perhaps between ca 2000 and 1300 yr BP (ca. 1700-1000 yr cal BP). These can be linked to phases of local sea level fall and/or phases of sedimentary starvation and/or changes in drift transport which can have produced local coastal cannibalization. However, no conclusive data can be advanced. Data obtained from careful measurements of sea level markers represented by the top of marsh and fluvial terraces indicate lower values for the sea level estimation compared with the data set previously proposed for the area. This stigmatizes the fact that field-oriented works are still the priority in the Patagonia coast along with accurate age measurement, especially for obtaining the fundamental information we need for predicting the environmental impact, in these coastal areas, from accelerate sea level rise as effect of global warming.
    Beschreibung: Published
    Beschreibung: 19-31
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.7. Dinamica del clima e dell'oceano
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Relative sea level ; sea level markers ; Patagonia ; Holocene ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 58
    Digitale Medien
    Digitale Medien
    Fundamental properties of fluoropolyether-based resins and related coatings (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 236 (1996), S. 111-127 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Neuartige Fluoropolyether-Polyol-Harze, die mit konventionellen Härtern wie Polyisocyanaten oder Melaminen aushärtbar sind, wurden hergestellt. Zunächst wurden oligomere NCO-terminierte Prepolymere durch Addition von Fluorpolyether-Makrodiolen unterschiedlicher Molekulargewichte an Isophorondiisocyanate erhalten. Durch die Reaktion dieser Prepolymeren mit Trimethylolpropan wurden endständige Hydroxygruppen eingeführt. Die Viskosität von Lösungen dieser Harze wurde bei unterschiedlichen Konzentrationen (Massenbruch 0,4-0,8) und Temperaturen (25°C-65°C) gemessen. Die erhaltenen Werte wurden auf der Basis der Erickson-Gleichung (Konzentrationsabhängigkeit von η) und unter Berücksichtigung des WLF-und des Arrhenius-Modells (Temperaturabhängigkeit von η) diskutiert. Das thermische Verhalten der Harze und von ausgehärteten Filmen wurde mit DSC bestimmt. Dabei wurden zwei Glasübergange beobachtet, die den separierten fluorhaltigen und nicht-fluorhaltigen Phasen zugeordnet werden können. Die Analyse des Zugverhaltens der Filme zeigte besonders bei den mit Isocyanat gehärteten Proben ein ausgeprägtes hart-plastisches Verhalten. Diese Werkstoffe erscheinen für die Anwendung als hoch-wertige, dauerfeste und klare Beschichtungen geeignet.
    Notizen: New fluoropolyether polyolic resins are presented suitable to be cured with conventional hardeners as polyisocyanates or melamines. These resins are prepared by addition of fluoropolyether macrodiols (Fomblin® ZDOLTX) of various molecular weights to isophorone diisocyanate (IPDI) to give oligomeric NCO-terminated prepolymers. The final hydroxy functionality is obtained by the reaction of those prepolymers with trimethylolpropane (TMP). The viscosity of the resins is measured at various concentrations (weight fraction 0.8 - 0.4) and temperatures (T = 25-65°C). The results are discussed in terms of the Erickson equation (η vs. concentration) and using the WLF and Arrhenius models (η vs. T). The thermal behavior is studied by DSC for both the resins and cured films indicating the presence of two Tgs, corresponding to the segregated fluorinated and hydrogenated phases, the former particularly evident with the highest molecular weights of the fluorinated macromer. Tensile curves of selfsupported films are then analyzed showing an evident tough-plastic behavior especially for the isocyanate-cured films. The application of such materials as high-durability clear coats is finally proposed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052360109
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  • 59
    Digitale Medien
    Digitale Medien
    Modification of melamine-formaldehyde moulding compounds with epoxy resins (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 237 (1996), S. 1-44 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Zur Verbesserung der Maßhaltigkeit und der Zähigkeit von gehärteten Melamin-Formaldehyd-Harz-Formmassen (MF) wurden teilverträgliche, methylolgruppenhaltige Epoxidharze (EP) auf Bisphenol A-Basis hergestellt und charakterisiert. Die Vernetzung solcher Epoxyresolharze durch 2-Ethyl-4-methylimidazol in Gegenwart von MF-Harz wurde untersucht. Spritzgepreßte Probekörper zeigen eine Zweiphasenstruktur; die EP-Phase kann als Wirt für carboxy-funktionalisierte, oligomere NBR-Kautschuke (CTBNX) dienen, die für sich allein in MF-Harzen nicht wirksam sind. Unter der Voraussetzung von kovalenten Bindungen in der Phasengrenzfläche kann durch den Zusatz von 0,5 bis 4 Gew.-% CTBNX zur MF-Formmasse bei EP-Anteilen bis 20 Gew.-% eine 50 bis 100proz. Steigerung von Bruchdehnung und Schlagzähigkeit erreicht werden, ohne daß Steifigkeit und Wärmeformbeständigkeit wesentlich abfallen. Bei moderaten EP/CTBNX-Gehalten wird zusätzlich die Nachschwindung von MF-Formteilen vermindert.
    Notizen: In order to improve dimension stability and toughness of melamine formaldehyde moulding materials (MF), compatible bisphenol A epoxy resins (EP) with additional methylol groups were synthesized and characterized. Crosslinking of those epoxyresol resins with 2-ethyl-4-methylimidazole in the presence of MF resin was investigated. Transfer-moulded specimens revealed a two-phase morphology in which the EP phase is used as a host for modification with carboxylic functionalized oligomeric NBR rubber (CTBNX), which is not effective in MF moulding materials alone. The addition of 0.5 - 4 wt.-% CTBNX to the MF moulding materials at an epoxy content of maximum 20 wt.-% results in 50-100 % increase of elasticity and toughness without serious decrease in stiffness and heat deflection temperature, provided that covalent interfacial bonds exist. In addition, the post-shrinkage of MF parts decreases if a moderate EP/CTBNX content is introduced.
    Zusätzliches Material: 26 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052370101
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  • 60
    Digitale Medien
    Digitale Medien
    New poly(vinyl chloride) blends, IIIPart II cf.5.. Physico-mechanical properties (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 238 (1996), S. 11-30 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Der gleichzeitige Einfluß des Verhältnisses von Fließhilfsmittel (Paraloid K 120N), Rußart und Schlagzähmodifikator (CPE 3615 und Kane Ace B56 A) auf die wichtigsten physiko-mechanischen Eigenschaften unplastifizierter PVC-Mischungen wurde studiert.Die erhaltenen Resultate wurden mathematisch verarbeitet und graphisch als Funktionsflächen dargestellt. Bemerkenswert ist, daß die Einführung von 2,5 und 5 Teilen Ruß eine Verbesserung der physico-mechanischen Eigenschaften ermöglicht. Dieses Resultat ist durch die Anwesenheit der Schlagzäh- und Fließmodifikatoren zu erklären.
    Notizen: The concurrent influence of the processing aid (Paraloid K 120N) and the carbon black ratio, as well as the nature and the ratio of the impact modifier (CPE 3615 and Kane Ace B56 A) on the main physico-mechanical characteristics of the poly(vinyl chloride)-based unplasticized mixtures have been studied. The results obtained, processed mathematically and plotted graphically in the form of response surfaces, evidenced that the improvement of certain physico-mechanical properties becomes possible by the introduction of 2.5 parts and 5.0 parts carbon black into these compounds. This is due to the introduction of impact modifiers and processing aids into the mixtures.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052380102
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  • 61
    Digitale Medien
    Digitale Medien
    New polyhydrazides and poly(1,3,4-oxadiazole)s containing pendent phenoxy groups (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 238 (1996), S. 63-71 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Eine Reihe neuartiger Polyhydrazide mit endständigen Phenoxygruppen wurde aus äquimolaren Anteilen von Dicarbonsäuredichloriden und Phenoxyterephthalsäuredihydrazid durch Lösungspolykondensation in N-Methyl-2-pyrrolidinon (NMP) bei niedriger Temperatur hergestellt. Durch thermische Cyclisierung der Polyhydrazide wurden die entsprehchenden Poly(1,3,4-oxadiazol)e mit endständigen Phenoxygruppen erhalten. Die Polymeren wurden durch Viskosimetrie, Löslichkeitsuntersuchungen, IR-Spektroskopie, Differentialkalorimetrie und Thermogravimetrie charakterisiert.
    Notizen: A series of new polyhydrazides containing pendent phenoxy groups has been synthesized by low-temperature solution polycondensation of equimolar amounts of diacid dichlorides and 2-phenoxyterephthalic dihydrazide in N-methyl-2-pyrrolidi-none (NMP). The thermal cyclization of the polyhydrazides gave the corresponding poly(1,3,4-oxadiazole)s containing pendent phenoxy groups. The polymers were characterized by viscometry, solubility measurements, IR spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052380106
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  • 62
    Digitale Medien
    Digitale Medien
    Effect of electron beam radiation on mechanical and electrical properties of poly(ethylene-co-vinyl acetate) (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 238 (1996), S. 105-117 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Ein Ethylen-Vinylacetat-Copolymeres (EVA) mit 12% Vinylacetat-Gehalt wurde mit Trimethylolpropantrimethacrylat (TMPTMA) als Sensibilisator mit Elektronen bestrahlt. Die mechanischen und elektrischen Eigenschaften der bestrahlten Copolymerproben wurden untersucht. Die Resultate zeigen, daß sich Zugfestigkeit und Bruchdehnung zunächst mit zunehmender Strahlungsdosis verbessern und bei Überschreiten einer optimalen Strahlungsdosis und Sensibilisatorkonzentration wieder verschlechtern. Durch die Bestrahlung wird eine Vernetzung des Polymeren ausgelöst, die auf den sich mit der Strahlungsdosis erhöhenden Gelanteil zurückgeführt wird. Im Vergleich mit den Originalproben nehmen sowohl die Dielektrizitätskonstante als auch der dielektrische Verlustfaktor durch die Elektronenbestrahlung ab.
    Notizen: Ethylene-vinyl acetate (EVA) copolymer (12% vinyl acetate content) is subjected to electron beam irradiation using trimethylolpropane trimethacrylate (TMPTMA) as a radiation sensitizer. Mechanical and electrical studies of these irradiated samples show that the strength properties (tensile strength, elongation at break) are increased with radiation dosage up to an optimum radiation dose and sensitizer level above which the properties begin to deteriorate. Crosslinking of the polymer takes place on irradiation which is attributed to an increased gel content with increasing radiation dose. Compared to the original samples both dielectric constant and dielectric loss factor decrease for samples subjected to irradiation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052380110
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  • 63
    Digitale Medien
    Digitale Medien
    Homogeneous synthesis of cellulose p-toluenesulfonates in N,N-dimethylacetamide/LiCl solvent system (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 238 (1996), S. 143-163 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Cellulose-p-toluolsulfonsäureester (Cellulosetosylate) lassen sich durch homogene Umsetzung von Cellulose in einer Lösung aus N,N-Dimethylacetamid und LiCl mit Tosylchlorid (Tos-Cl) und Triethylamin in 24 h bei 8°C in hoher Ausbeute und mit minimalem Einbau von Chlordesoxy-Gruppen herstellen. Die unterschiedlichen Celluloseausgangsmaterialien hatten durchschnittliche Polymerisationsgrade von 280 bis 5100. Die Produkte wurden mit Elementaranalyse, 13C-NMR- und FTIR-Spektroskopie und durch Bestimmung der Grenzviskositäten charakterisiert. Die Erhöhung des Molverhältnisses Tos-Cl/Anhydroglucose-Einheit (AGU) von 0.6 auf 9.0 führte zu einem Anstieg des Substitutionsgrades (DS) von 0.4 bis auf einen Maximalwert von 2.3. Die Cellulosetosylate sind in herkömmlichen organischen Lösungsmitteln wie Dimethylsulfoxid (im gesamten DS Bereich) und in N,N-Dimethylacetamid, N,N-Dimethylformamid, Aceton, Tetrahydrofuran und Trichlormethan (in Abhängigkeit von DS) löslich. Durch 13C-NMR-Spektroskopie wurde nachgewiesen, daß die Tosylierung am O-6 Atom der AGU schneller als an den O-2/3 Atomen erfolgt. Die Analyse der korrespondierenden Ioddesoxycellulosen, die durch Umsetzung mit NaI in Acetylaceton synthetisiert wurden, bestätigte dies zusätzlich. Darüber hinaus wurden wichtige Eigenschaften der Cellulosetosylate wie die Stabilität gegenüber Alkali und thermischer Beanspruchung untersucht.
    Notizen: Pure cellulose p-toluenesulfonates (tosylates) with an insignificant formation of chlorodeoxy groups were prepared by reacting cellulose dissolved in a solution of N,N-dimethylacetamide and LiCI with tosylchloride (Tos-CI) in the presence of triethylamine within 24 h at 8°C. Various cellulosic starting materials with a degree of polymerization from 280 to 5 100 were used. The samples obtained were characterized by means of elemental analysis, FTIR and 13C NMR spectroscopy, and their intrinsic viscosities. The rise of the molar ratio of Tos-CI/anhydroglucose unit (AGU) from 0.6 to 9.0 leads to an increase in the degree of substitution (DS) from 0.4 up to a maximum value of 2.3. The cellulose tosylates are readily soluble in common organic solvents like dimethyl sulfoxide (within the whole DS range) and in N,N-dimethylacetamide, N,N-dimethylformamide, acetone, tetrahydrofuran and trichloromethane depending on DS. As revealed by 13C NMR spectroscopy a faster tosylation takes place at the O-6 atom of AGU compared with the O-2/3 atoms. This was additionally confirmed by analysis of the corresponding iododeoxy celluloses synthesized with NaI in acetylacetone. Furthermore, some important properties as stability against alkaline and heat were studied as well.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052380113
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  • 64
    Digitale Medien
    Digitale Medien
    Coating of carbon-fiber surface by silicon carbide via sol-gel mixtures of tetraethyl orthosilicate and phenolic resin (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 27-32 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die Herstellung einer SiC-Oberfläche auf Kohlefasern unter Verwendung einer Sol-Gel-Mischung von Tetraethylorthosilikat (TEOS) und Phenolharz wurde untersucht. FTIR- und SEM-Untersuchungen zeigten, daß die SiC-Oberfläche durch carbothermische Reduktion der Sol-Gel-Mischung bei 1 420°C innerhalb von 15-20 min in einer Argon-Atmosphäre gebildet werden kann. Mittels TGA konnte gezeigt werden, daß die SiC-Beschichtung die thermo-oxidative Stabilität der Kohlefasern erhöht. Bei der erreichten SiC-Schichtdicke von 0,47 μm, bei einem C/Si-Verhältnis von 4, zeigt sich keine Beeinflussung der mechanischen Stabilität der Kohlefasern.
    Notizen: The preparation of a SiC coating on a carbon fiber surface using a sol-gel mixture of tetraethyl orthosilicat (TEOS) and phenolic resin was studied. FTIR and SEM investigations indicated that the SiC coating can be formed by carbothermal reduction of the sol-gel mixture at 1420°C for 15-20 min in an argon atmosphere. TGA of the coated fiber was also performed, showing that the SiC coating improves the thermooxidative stability of the carbon fiber. With the thickness of the obtained coating of 0.47 μm using a C/Si ratio of 4, this treatment does not affect the carbon fiber strength.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390103
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  • 65
    Digitale Medien
    Digitale Medien
    Adhesive properties of some pressure-sensitive adhesive agents containing oligomer additives (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 55-62 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Diese Mitteilung behandelt den Einfluß von oligomeren Polypropylen- und Polybutylenölen mit unterschiedlichem Molekulargewicht auf die adhäsiven Eigenschaften von ataktischem Polypropylen (aPP) und dessen Mischungen mit einem Styrol-Ethylhexylacrylat-Copolymeren. Die mechanische Adhäsionsarbeit Am von Mischungen, die ataktisches Polypropylen und das Oligomere enthalten, steigt mit dem Molekulargewicht des Oligomeren, was im Fall des Propylenöls signifikanter ist. Im Fall der ternären Mischungen des ataktischen Polypropylens mit dem Styrol-Ethylhexylacrylat-Copolymeren und Oligomeren wird ein Adhäsions-Maximum beobachtet, wenn der Gehalt an Styrol-Ethylhexylacrylat-Copolymeren in der Mischung ungefähr 30 Gew.-% erreicht. Wenn kein Oligomeres in der Mischung vorhanden ist, kann man bei dieser Zusammensetzung ein Adhäsions-Minimum beobachten, was auf die Unverträglichkeit der übrigen Komponenten zurückzuführen ist.
    Notizen: This paper deals with the influence of oligomers, namely propylene oil and butylene oil, of different molecular weight on the adhesive properties of atactic polypropylene (aPP) and its mixtures with styrene-2-ethylhexyl acrylate (S-EHA) copolymer. The mechanical work of adhesion Am of the mixture containing atactic polypropylene and oligomer increases with the molecular weight of the oligomer, which was more significant in the case of propylene oil. For ternary mixtures aPP-S-EHA copolymer/oligomer a maximum of adhesion can be observed if the content of the S-EHA copolymer in the mixture reaches about 30 mass-%. In the absence of oligomers in the mixture a minimum of adhesion can be observed for this composition, which can be attributed to the incompatibility of the remaining components.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390106
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  • 66
    Digitale Medien
    Digitale Medien
    Untersuchungen zur synthese von poly(butadien-co-propylenoxid) mit einem ziegler-natta-titankatalysatorsystem (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 107-119 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: After comparison of three catalyst systems, i.e. [Nd(Oct)3/Al2Cl3ET3/Al(i-But)3, Ni(Oct)2/BF3OEt2/AlEt3 and Al(i-But)3/I2/TiCl4] the titanium catalyst system was used for the copolymerization of 1,3-butadiene with propylene oxide. The effects of monomer ratio on copolymer composition, conversion, microstructure, molar mass and molar mass distribution as well as of time of polymerization and of the aluminium/titanium ratio were evaluted. The copolymerization parameters were determined according to Kelen-Tüdős as rbutadiene = 0,9 and rpropylene oxide = 3,9. Copolymerization was confirmed by 13C NMR spectroscopy and extract evaluation combined with 1H NMR spectroscopy.
    Notizen: Für die Copolymerisation von 1,3-Butadien mit Propylenoxid wurde nach dem Vergleich der drei Katalysatorsysteme Nd(Oct)3/Al2Cl3ET3/Al(i-But)3, Ni(Oct)2/ BF3OEt2/AlEt3 und Al(i-But)3/I2/TiCl4 das Titankatalysatorsystem eingesetzt. Neben dem Einfluß der Monomerzusammensetzung auf den Umsatz, die Microstruktur, die Copolymerzusammensetzung, die Molmassen sowie die Molmassenverteilungen wurden auch die Polymerisationszeit und das Aluminium/Titan-Verhältnis untersucht. Die Copolymerisationsparameter wurden nach Kelen-Tüdős zu rButadien = 0,9 und rPropylenoxid = 3,9 bestimmt. Der Copolymernachweis erfolgte über 13C-NMR-Spektroskopie und Extraktionsuntersuchungen in Verbindung mit 1H-NMR-Spektroskopie.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390110
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  • 67
    Digitale Medien
    Digitale Medien
    Phosphorus-containing polyurethanes based on bisphenol A via N-alkylation (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 191-199 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Phosphorhaltige Polyurethane (PU-P) auf der Basis von Bisphenol A wurden durch N-Alkylierung hergestellt und mittels IR- und 1H NMR-Spektroskopie charakterisiert. Physikalische und thermische Eigenschaften dieser Polyurethane wurden mittels Differentialkalorimetrie, Thermogravimetrie, Röntgenbeugung und Untersuchungen der Löslichkeit, der Feuerbeständigkeit (Sauerstoffindex, LOI) und der reduzierten Viskosität bestimmt. Die Glastemperaturen der N-alkylierten Polymeren sanken von 120°C für das Ausgangspolymere bis auf 29°C für das N-alkylierte Polyurethan mit 2 Gew.-% Phosphor. Die Viskosität der N-alkylierten Polyurethane nahm von 0,36 dL g-1 auf 0,24 dL g-1 ab. Die phosphorhaltigen Polyurethane besitzen eine geringere thermische Stabilität und bessere Löslichkeit sowie höhere Feuerbeständlgkeit als das Ausgangspolymere. Die Röntgenstreuexperimente ergaben, daß ein erhöhter Phosphorgehalt der Polyurethane die Kristallinität herabsetzt.
    Notizen: Phosporus-containing polyurethanes (PU-P) based on bisphenol A were prepared by N-alkylation. The structures of N-alkylated polyurethanes were characterized by IR and 1H NMR spectra. Physical and thermal properties of the phosphorus-containing polyurethanes were investigated with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction, tests of solubility, limiting oxygen index (LOI) and reduced viscosity. Tg of the N-alkylated polymers decreased from 120°C for the starting polymer to 29°C of the 2.0 wt.-% phosphorus-containing polyurethanes. The viscosity of N-alkylated polyurethanes also decreased from 0.36 dL g-1 to 0.24 dL g-1. The thermal stability of polyurethanes decreased on the introduction of phosphorus groups. The LOI values of polyurethanes showed that fire resistance of phosphorus-containing polyurethanes was enhanced. X-ray diffraction measurements showed that the increased phosphorus content was accompanied by decreased crystallinity of the polyurethanes. The solubility of PU-P was improved.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390116
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  • 68
    Digitale Medien
    Digitale Medien
    Are cured thermoset resins inhomogeneous?Lecture presented at International Symposium on Advanced Network-Polymers, Kansai University (ISANKU), at Kansai University, Suita, Osaka, Japan, on December 5-6, 1995 (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 1-15 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: This question was addressed using various methods to monitor the process of curing and state of the final network. Attention was particularly focused on the possible inhomogeneous network formation as a consequence of the crosslinking process. An analysis of experimental data has revealed that some cured resins can be considered as homogeneous as the corresponding uncrosslinked materials. Resins cured by simple stepwise alternating chemistries, with good compatibility of components, usually fulfill the criterion of homogeneity. A family of epoxy resins cured with polyamines belongs to this category. Nodular structures seen by electron microscopy are a result of interaction of the electron beam or etching. Such structures are also observed for uncrosslinked polymers investigated under the same conditions. Formation of inhomogeneities in a number of thermoset systems is due to (a) chainwise mechanism of network formation with fast propagation inducing cyclization and steric volume exclusion and (b) poor compatibility of components of the system made stronger by increasing molecular weights and crosslinking during curing. Networks formed by freeradical polymerization and copolymerization of polyvinyl monomers can serve as an example of crosslinking-driven formation of inhomogeneities.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400101
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  • 69
    Digitale Medien
    Digitale Medien
    Design of network polymers by photopolymerizationLecture presented at the “International Symposium on Advanced Network Polymers, Kansai University” (ISANKU), at Kansai Univeristy, Suita, Osaka, Japan, on December 5-6, 1995. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 83-90 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The base and transition metal catalyzed isomerization of allyl and crotyl ethers affords a facile, high yield route to the preparation of a variety of mono-, di-, and multifunctional 1-propenyl and 1-butenyl ethers. Employing this novel method, monomers containing epoxide, ester, ether carbonate and urethane groups can be prepared from their readily available allyl and crotyl precursors. In general, these monomers display very high reactivity in cationic polymerizations. In our work, we have focused on photoinduced cationic polymerizations of these monomers using diaryliodonium and triarylsulfonium salt photoinitiators. To study these very fast photopolymerizations, extensive use of real-time infrared spectroscopy was made. Employing this technique, the effects of monomer and photoinitiator structure on the rates of polymerization were studied.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400107
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  • 70
    Digitale Medien
    Digitale Medien
    Designing elastomer network for desired tire performance characteristics (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 137-149 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Rubber elasticity is associated with changes in configurational entropy of a long chain. Because the chain cannot change its configuration instantaneously, there is a time delay in deformation to an applied force. This delayed response is the source of viscoelasticity and hysteresis energy loss of elastomer networks. Many tire performance properties are related to the viscoelasticity of tire components. Wet and dry traction of tire is related to the energy loss of the tread material at very high frequencies. On the other hand, rolling resistance of tire is characterized by the energy loss of tread material at relatively low frequencies. The dynamic viscoelastic properties of elastomer network shows characteristic zones on a frequency scale. At very high frequencies the energy loss is controlled by the segmental motions of the polymer chain. At lower frequencies the energy loss is related to the longer range motions of the chain. A series of polymers was synthesized to study the effect of micro- and macro-structure of the polymer on the viscoelastic properties of tread compounds and their tire performance properties. As expected from the theory, the wet traction of the tire was highly correlated to the segmental motions of the chains; namely, the glass transition temperature of the polymer. The energy loss of the compounds at a higher temperature, however, was related to the macrostructure of the polymer chain. Those examples illustrate that the fundamental understanding of the theory of elastomer network allows a tire engineer to obtain the best balance of tire performance characteristics.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400112
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  • 71
    Digitale Medien
    Digitale Medien
    Molecular design of novel network polymers (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 171-180 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Cationic, anionic, and radical ring-opening polymerization of spiro and bicyclic monomers, and their application to network polymers have been developed. Bicyclo orthoesters (BOEs), spiro orthoesters (SOEs), and spiro orthocarbonates (SOCs) were polymerized by cationic double ring-opening. Bicyclobis(γ-butyrolactone)s and spirobis(γ-butyrolactone)s were copolymerized with epoxides by anionic alternating ring-opening. Polymers from SOCs bearing exomethylene groups consisted of ring-opened and vinyl polymerized units. The degree of ring-opening of SOCs depended upon the number of rings and steric hindrance. The radical polymerization of vinylcyclopropanone cyclic acetals depended on the ring-size. With the monomers bearing 5- and 6-membered acetal rings, single ring-opened polymers were obtained. With the monomer bearing 7-membered acetal ring, the polymer mainly consisted of double ring-opened unit. These monomers could be crosslinked by bifunctionalization. Poly(cyclic orthoester)s linked by covalent bonds with dithiols to bifunctional SOEs were crosslinked by acid catalysts, and the reversible crosslinking-depolymerization system could be controlled by temperature.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400115
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  • 72
    Digitale Medien
    Digitale Medien
    Characterization of polyurethane network elastomers (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 205-211 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Polyester urethane network elastomers with incorporated hard segment oligomers have been prepared by poly(ethylene adipate)glycol (PEA), 2,4-tolylene diisocyanate (TDI), and 1,4-butanediol (BD). These hard segment oligomers were hydroxy-terminated oligomers ([BD-TDI]n-BD; n=1,3), obtained by reacting BD with TDI. Concentrations of allophanate as a cross-linking site were determined by the amine degradation method. Hard segment moieties were obtained by a novel selective hydrolysis of soft segments in the elastomers. Molecular weight distributions of hard segment were measured by means of GPC. Mechanical and thermal properties were measured. Dependence of rubber elasticity on physical cross-linking between normal elastomers and the elastomers with incorporated hard segment oligomers were discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400119
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  • 73
    Digitale Medien
    Digitale Medien
    Network formation and swelling behavior of photosensitive poly(vinyl alcohol) gels prepared by photogenerated crosslinkingPoster presented at the “International Symposium on Advanced Network-Polymers, Kansai University” (ISANKU), at Kansai University, Suita, Osaka, Japan, on December 5-6, 1995. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 231-239 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Poly (vinyl alcohol) with pendent styrylpyridinium groups (SbQ) is insolubilized by photoirradiation. An association takes place in SbQ groups. The association of polymer chains becomes marked with increasing the number of SbQ groups. Mainly intermolecular crosslinks were formed. Transparent and homogeneous macrogels consisting of several intermolecular crosslinks are obtained.The proportion of the free water to the bound water in PVA-SbQ gels was 3.3-2.9 despite of the large change in conversion of photodimerization of SbQ groups, x=0.27-0.58. The water uptake after swelling of the gels in water increased 6-27 times compared to the original weight at pH=7. The higher the degree of photocrosslinking, the lower was the degree of swelling. The water diffusion coefficients, D, were (2.2-5.8) × 10-5 cm2 S-1 for a 88% saponified PVA with 1 . 3 mol% SbQ groups. The volume of the gel increased discontinuously about 10-fold for the 99% saponified PVA with 0 . 096 mol% SbQ and 51% water (49% acetone). The acetone concentration at the transition decreased with increasing the degree of saponification of the PVA.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400122
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  • 74
    Digitale Medien
    Digitale Medien
    Hydrogels for biomedical use based on 1-vinyl-2-pyrrolidone crosslinked with macromonomers (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 151-160 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Durch anionische Copolymerisation von Allylmethacrylat und Methylmethacrylat wurden Makromonomere unterschiedlicher Kettenlänge mit durchschnittlich drei Allyl-Doppelbindungen pro Kette hergestellt́ und mit NMR-Spektroskopie und Gelpermeationschromatographie charakterisiert. Durch Copolymerisation der Makromonomeren mit 1-Vinyl-2-pyrrolidon wurden dreidimensionale Strukturen erhalten. Die optischen und mechanischen Eigenschaften der Produkte wurden untersucht, und die Quellungseigenschaften und Vernetzungsgrade wurden bestimmt. Die Copolymereigenschaften wurden durch Makromonomere mit Kettenlängen bis 40 Einheiten nur wenig beeinflußt. Bei Kettenlängen über 50 Einheiten wurde eine leichte Abnahme der Wasseraufnahmefähigkeit und eine deutliche Erhähung des Elastizitätsmoduls beobachtet. Die Vernetzungsgrade hängen von der Makromonomer-Kettenlange ab; eine merkliche Erhöhung aufgrund der groößeren Zahl an Methyl-Methyl-Wechselwirkungen wurde bei Kettenlangen über 50 Einheiten festgestellt. Die Copolymeren zeigen günstige Festigkeits-Dehnungs-Eigenschaften und einen geringen Gehalt an wasserlöslichen Extrakten, in denen durch IR-Spektroskopie 1-Vinyl-2-pyrrolidon-Homopolymere identifiziert wurden. Obwohl mit allen untersuchten Makromonomeren gute Resultate erzielt wurden, scheint für die Copolymerisation mit 1-Vinyl-2-pyrrolidon das Makromonomere mit 50 Einheiten am besten geeignet.
    Notizen: Macromonomers of various chain lengths with an average of three allyl double bonds per chain were prepared by anionic copolymerization of allyl methacrylate with methyl methacrylate. The macromonomers were characterized by gel permeation chromatography and nuclear magnetic resonance. The macromonomers were then copolymerized with 1-vinyl-2-pyrrolidone to form three-dimensional structures. Their optical, swelling and mechanical properties were studied and the crosslinking efficiency was determined. The copolymer properties are not greatly affected by macromonomer chain lengths up to 40-mers; above 50-mers there is a slight decrease in the equilibrium water content and a significant increase in the modulus of elasticity. The crosslinking efficiency depends on the macromonomer chain length; a marked increase was observed for the 50-mer because of a greater number of methyl-methyl interactions. Copolymers have favourable strength-strain properties and a low content of water-soluble extracts, in which the IR analysis demonstrated the presence of 1-vinyl-2-pyrrolidone homopolymers. In spite of the good results obtained for all the macromonomers described in this work, the 50-mer seems to be optimal for copolymerization with 1-vinyl-2-pyrrolidone.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390113
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  • 75
    Digitale Medien
    Digitale Medien
    Zur härtung von diandiglycidylether mit anhydridmodifizierten phenolischen härtern und zu vergleichbaren in situ-reaktionen (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 201-213 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: The curing of diglycidyl ether of bisphenol A (DGEBA) with 2,6-dimethylol-p-cresol modified by hexahydrophthalic acid anhydride was investigated and compared with the analogous in situ curing of DGEBA, hexahydrophthalic acid anhydride and 2,6-dimethylol-p-cresol. The chemical reactions were investigated by means of titration and different spectroscopic and chromatographic methods. It was examined whether the less complicated and therefore cheaper in situ reaction delivers postcured products with equal or better properties. Furthermore, it was investigated whether the results are similar using technical phenolic hardeners.
    Notizen: Die Härtung von Diandiglycidylether (DDGE) mit hexahydrophthalsäureanhydridmodifiziertem 2,6-Dimethylol-p-kresol (HHPSA-DMPK) wurde untersucht und mit der in situ durchgeführten Vernetzung von DDGE mit Hexahydrophthalsäureanhydrid (HHPSA) und 2,6-Dimethylol-p-kresol (DMPK) verglichen. Die chemischen Reaktionen wurden durch Titration der Epoxidgruppen und mit verschiedenen spektroskopischen und chromatographischen Methoden untersucht. Es wurde geprüft, ob die weniger aufwendige und daher preiswertere in situ-Härtung zu Produkten mit gleichen oder besseren Endeigenschaften führt. Weiterhin wurde die Übertragbarkeit der Ergebnisse auf den Einsatz technischer Phenolharzhärter getestet.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390117
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  • 76
    Digitale Medien
    Digitale Medien
    Characterization and application of poly(vinyl alcohol)/starch composite as a sizing agentResults published in this paper were extracted from the Ph. D. Thesis to be submitted by M. M. Hashem to Cairo University, Egypt. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 241 (1996), S. 149-163 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Zur Entwicklung neuartiger ökologisch verträglicher makromolekularer Schlichtemittel wurden in früheren Arbeiten Copolymerisationsreaktionen zwischen Polyvinylalkohol (PVA) und Stärke unter Verwendung von chemisch reaktiven bifunktionellen Verbindungen wie N-Methylolacrylamid beschrieben. Im Rahmen dieser Arbeit werden die physikochemischen Eigenschaften des resultierenden Copolymeren untersucht. Von Bedeutung sind hierbei insbesondere Merkmale wie Molekulargewichtsverteilung, Klebekraft, Stabilität, Löslichkeit sowie rheologische Eigenschaften. Derartige Kenntnisse über die physikochemische Beschaffenheit der PVA-Ausgangsverbindung sowie des makromolekularen Endproduktes sind eine wesentliche Voraussetzung für die Entwicklung von neuen Produkten, die als wasserlösliche, recycelbare Schlichtemittel zur Anwendung in der Textilindustrie kommen können.
    Notizen: A macromolecular sizing agent based on the copolymerization of poly(vinyl alcohol) (PVA) with hydrolysed starch was prepared using the chemically reactive bifunctional compound N-methylolacrylamide. Detailed characteristics of the resultant PVA/N-methylolcarbamoylethylated starch copolymer were studied where emphasis has been placed on solubility, rheological properties, molecular weight distribution, adhesive power and stability. Elucidation of the nature of the macromolecular segments of both N-methylolcarbamoylethylated PVA as well as PVA/N-methylolcarbamoylethylated starch copolymer fulfilled the prerequisite to tailor PVA/starch copolymer which is appropriate for application as a water-soluble recyclable sizing agent by ultrafiltration.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052410112
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  • 77
    Digitale Medien
    Digitale Medien
    Peripherally restraining type rubber bearingLecture presented at the “International Symposium on Advanced Network-Polymers, Kansai University” (ISANKU), at Kansai University, Suita, Osaka, Japan, on December 5-6, 1995. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 151-162 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Seismic isolation was reconfirmed to be extremely efficient for the protection of buildings, and hence human life, on the occasion of the Great Hanshin Earthquake. Rubber bearings are placed under the buildings for isolation, and thus the type of rubber bearings is a dominant factor for efficient isolation. In this report, the performance of peripherally restraining type rubber bearing (PRB) was examined where its contracted model was found to simulate the performance of full scale PRB precisely. Damping ratio and vertical spring constant of PRB are as good as the existing ones. PRB showed lower critical shear strain, but it was concluded that no problems were found for the actual use of PRB.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400113
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  • 78
    Digitale Medien
    Digitale Medien
    Computational study of network formation of phenolic resinsPoster presented at the “International Symposium on Advanced Network-Polymers, Kansai University” (ISANKU), at Kansai University, Suita, Osaka, Japan, on December 5-6, 1995. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 181-186 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The network formation of phenol-formaldehyde resin was investigated by the Monte Carlo (MC) simulation technique. The observed value of the gel point, pc, was exactly determined as a critical extent of reaction, where the Mw/Mn in soluble parts is maximum. The MC simulation with the cubic percolation theory was applied to the gelation of phenolic resins and gave an exact gel point, which was in excellent agreement with the observed value of pc. The simulation showed that the intramolecular reaction occurred frequently with increasing the gel fraction beyond the gel point. The structural analysis of the maximum cluster with the computer strongly supported the contribution of the intramolecular reaction to the network formation of the gel.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400116
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  • 79
    Digitale Medien
    Digitale Medien
    PH-induced structure change of poly(vinyl alcohol) hydrogel crosslinked with poly(acrylic acid)Poster presented at the “International Symposium on Advaned Network-Polymers, Kansai University”(ISANKU), at Kansai University, Suita, Osaka, Japan, on December 5-6, 1955. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 213-219 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The structure of the hydrogel of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) was investigated by small angle X-ray scattering (SAXS) of synchrotron radiation. A physically crosslinked blend gel, which was prepared by repetitive freezing and thawing of an aqueous solution of PVA and PAA, could be chemically crosslinked by esterfication of PVA with PAA even in the hydrogel state. The chemical crosslinking induced the destruction of physical crosslinks into a folded structure, indicating that the chemical crosslinking proceeds at the sites around the physical crosslinks that contain PVA and PAA in much higher concentration than other portion of the gel. The pH-induced structure changes of the PVA hydrogels, chemically crosslinked with poly(acrylic acid) (PAA) were investigated by SAXS on the samples of various chemical crosslinking time. The gels were shrunk at pH4, and swollen at pH8. The results of SAXS showed, that the Porod slope changed with chemical crosslinking time from -3.5 to -2.9 at pH4, and from -2.9 to -2.4 at pH8. The results suggest that a folded structure as a structural domain, which is characterized by fractally rough interface, tends to change into the structure that corresponds to percolation cluster, particularly at pH8. The gels immersed in pH8 showed a remarkable structure change accompanying swelling. The results revealed that a conformational change of PAA chains, induced by the pH change, can be explained by the presence of a structural domain in the gel network, where both PVA chains and PAA chains get entangled and partially form a interpenetrating polymer network(IPN).
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400120
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  • 80
    Digitale Medien
    Digitale Medien
    Polyurethane-elastomer-actuatorPoster presented at the “International Symposium on Advanced Network-Polymers, Kansai University” (ISANKU), at Kansai University, Suita, Osaka, Japan, on December 5-6, 1995. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 221-229 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Polyurethane elastomers were investigated as electrically active materials for actuators. Components in hard segment and soft segment in the elastomers were varied. The elastomers with excellent electrostrictive properties were limited to those which had soft segments of polyesters and polylactones. It turned out, that the elastomers, whose soft segments are polyethers are electrically inert under the experimental conditions. The chemical structure of the hard segment seems not to influence to the electrostrictive property. The charging and discharging process was investigated. The charging process was found to proceed simultaneously with the contracting process caused by the electric field, suggesting that the orientation of the soft segment in the elastomer plays critical rolls in the electrostrictive action. In the elastomer, which has a soft polyether segment and was inactive to the electric field, could be actuated very efficiently when the elastomer was swollen with dimethyl sulfoxide. We conclude that the polyurethane elastomer, whose soft segment has chemical bonds with a relatively large dipole moment, can be actuated by the electric field application, and that even the elastomer, whose soft segment is inactive, could be actuated in the presence of a solvent with a large dipole moment. Thus, the concept found with the gel, could be applied to an elastomer, the soft segment of which plays partly the roll of the solvent in the gel.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400121
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  • 81
    Digitale Medien
    Digitale Medien
    Preparation of oxidized 6-O-glycolchitosan, pH sensitivity of its aqueous solution and of its cross-linked hydrogel (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 263-273 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Chitosan and 6-O-glycolchitosan, a water-soluble chitosan derivative, were oxidized by periodate. In the case of chitosan, only degradation products were obtained. With 6-O-glycolchitosan, however, water-soluble amphoteric polyelectrolyte derivatives of chitosan having higher molecular weight were obtained. The oxidized 6-O-glycolchitosan (OX-GC) showed a pH sensitive change of viscosity in aqueous solution. Moreover, the OX-GC hydrogel, cross-linked with glutaraldehyde, showed a pH sensitive swelling behavior. The OX-GC showed biodegradation behavior by lysozyme after acetylation.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400125
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  • 82
    Digitale Medien
    Digitale Medien
    A polymer network of unsaturated polyester and bismaleimide resins: Yielding and fracture behaviour (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 241 (1996), S. 11-29 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Das Fließ- und Bruchverhalten eines durch das gleichzeitige Härten eines ungesättigten Polyesters (UP) und eines wärmehärtbaren Bismaleimidharzes (BMI) erhaltenen quervernetzten Polymernetzwerkes wurde über einen weiten Temperatur- und Beanspruchungsbereich untersucht. Die Fließspannung σy und der Youngsche Elastizitätsmodul E steigen bei Zunahme der Spannungsbeanspruchung bzw. bei Absinken der Temperatur. Zudem steigen bei ansonsten gleichen Testbedingungen σy und E mit zunehmendem BMI-Gehalt im Blend. Andererseits wurde eine Beeinflussung des Bruch-Parameters Kc durch die Gegenwart des BMI nicht beobachtet. Der Fließprozess wurde sowohl mit Hilfe der Theorie von Argon als auch mit der von Bowden untersucht; die daraus abgeleiteten Molekül-Parameter wurden mit der bei der Härtung gebildeten Molekularstruktur in Beziehung gesetzt.
    Notizen: The yielding and the fracture behaviour of an intercrosslinked polymer network obtained by the simultaneous curing of an unsaturated polyester (UP) and a thermosetting bismaleimide resin (BMI) was investigated in a wide range of temperatures and testing rates. The yield stress σy and the Young's modulus E increase by increasing the testing rate and decreasing temperature. Moreover, under the same testing conditions, σy and E increased as the BMI content in the blend was enhanced. On the other hand, it was found that the fracture parameter Kc was not affected by the presence of BMI. The yielding process was analyzed using the theories both of Argon and Bowden and the molecular parameters derived there were related to the molecular structure of the network developed upon curing.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052410102
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  • 83
    Digitale Medien
    Digitale Medien
    Fluorinated poly(1,3,4-oxadiazole-imide-amide)s (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 242 (1996), S. 159-169 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Dicarbonsäuredichloride mit sowohl Hexafluorisopropyliden-Brücken und Imidringen im Molekül wurden mit p-Aminobenzhydrazid oder Mischungen aus aromatischen Diaminen und p-Aminobenzhydrazid oder Terephthaldihydrazid zu Poly(hydrazidimid-amid)en umgesetzt, die anschließend zu neuen fluorhaltigen Poly(1,3,4-oxadiazol-imid-amid)en mit verschiedenem Amid/Oxadiazol-Verhältnis cyclodehydriert wurden. Diese sind in polaren amidischen Lösungsmitteln löslich; aus solchen Lösungen lassen sich flexible Filme herstellen. Die Glasübergangstemperaturen liegen zwischen 254°C und 325°C. Sie sind bis zu 415-450°C thermisch stabil.
    Notizen: A series of new fluorinated poly(1,3,4-oxadiazole-imide-amide)s containing various ratios of amide/oxadiazole groups in the repeating unit have been prepared by cyclodehydration of the corresponding poly(hydrazide-imide-amide)s resulting from the reaction of diacid dichlorides incorporating both hexafluoroisopropylidene bridges and imide rings with p-aminobenzhydrazide or with mixtures of certain aromatic diamines and p-aminobenzhydrazide or terephthalic dihydrazide. The new polymers are soluble in polar amidic solvents and can be processed into flexible films by casting from solution. Their glass transition temperatures are in the range 254-325°C and they are thermally stable up to 415-450°C.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052420111
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  • 84
    Digitale Medien
    Digitale Medien
    Electric resistivity of hydroscopic copoly(ester-ether)s containing zwitterionic units and their utilization for antistatic modification of polyester fiber (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 242 (1996), S. 171-181 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Blockcopoly(ester-ether) mit verschiedenen ionischen Einheiten wie Sulfobetain (S-Betain), Carbobetain (C-Betain) und Ammoniumtosylat wurden hergestellt und hinsichtlich ihrer Eignung als antistatische Modifikatoren für Polyethylenterephthalat (PET)-Fasern untersucht. Die ionischen Segmente wurden aus N,N-Bis(2-hydroxyethyl)methylamin generiert und statistisch mit den Polyester- und Polyoxyethylen(PEO)-Einheiten cokondensiert. Aus den Copolymeren mit S-Betain-Einheiten wurden im Schmelzspinnverfahren dicke Filamente hergestellt und deren elektrischer Widerstand bestimmt. Abhängig von der Zusammensetzung (25-75 Gew.-% PEO, 1-2 mol-% S-Betain) wurden Widerstände zwischen 108 und 1010 Ω cm-1 gemessen. Die drei copolymerartigen Modifikatoren wurden mit PET durch Blendspinnen gemischt. Die so erhaltenen PET-Fasem zeigen nicht nur gute mechanische sondern auch verbesserte antistatische Eigenschaften. Die Fasern aus dem S-Betain enthaltenden Copolymeren weisen dabei die kürzeste Halbwertszeit des Abbaus der elektrostatischen Ladung auf, obwohl der Oberflächenwiderstand dieses Materials in der Größenordnung 1013 Ω cm-2 dem Wert der mit C-Betain und Ammoniumtosylat hergestellten Fasem ähnlich ist. Die PET-Fasern bewahren ihre guten antistatischen Eigenschften auch nach dem Fäben und wiederholtem Waschen, da sowohl die hydrophilen als auch die ionischen Gruppen an den Polyesterketten fixiert sind.
    Notizen: Block copoly(ester-ether)s containing different ionic units, i.e., sulfobetaine (S-betaine), carbobetaine (C-betaine), and ammonium tosylate, were prepared and evaluated as antistatic modifiers of PET fiber. The ionic units were readily derived from N,N-bis(2-hydroxyethyl)methylamine and co-condensed randomly with the polyester and poly(oxyethylene) (PEO) units. For the copolymers containing S-betaine units, a thick filament was melt-spun to evaluate their apparent electric resistivity. Depending on the unit compositions (25-75 wt.-% of PEO and 1-2 mol-% of S-betaine), resistivities ranging from 108 to 1010 Ω cm-1 were obtained. Then, the three copolymer-type modifiers were blended with poly(ethylene terephthalate) (PET) by the ordinary blend-spinning technique. The blend PET fibers obtained showed not only good mechanical properties, but also improved antistatic properties. Particularly, the fiber blended with the copolymer containing S-betaine units had the shortest half-life time of leakage of static charge, although the surface area resistivity, being in the order of 1013 Ω cm-2, was similar to that of the fibers blended with the copolymers containing C-betaine and ammonium tosylate units. These blend PET fibers were found to retain good antistatic properties even after dyeing and repeated washings, because both the hydrophilic and ionic groups are immobilized with the polyester chains.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052420112
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  • 85
    Digitale Medien
    Digitale Medien
    Untersuchungen zum reaktionsverhalten beim vorliegen von depolymerisationsreaktionen. Untersuchung von copolymerisationen des α-methylstyrols (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 243 (1996), S. 11-37 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: For radical copolymerizations of α-methylstyrene (MS) with methacrylonitrile (MAN) and of MS with acrylonitrile (AN) studies were carried out to examine postulations of kinetic models known from literature, in particular the terminal model with chain-length-independent and chain-length-dependent depolymerization steps. The results of investigations were based on measurements of the sequence length distributions from 13C-NMR spectra. Analyses of MS/MAN copolymers with various compositions were carried out. Reaction parameters and depolymerization constants depending on temperature were calculated. The values of enthalpy and entropy of polymerization and the ceiling temperature were computed for MS to ΔH = 26,5 ± 0,5 kJ mol-1, ΔS = 95 ± 5 J mol-1 K-1, Tceiling = 65 ± 1°C. The terminal model with depolymerization steps turned out to be wrong for the accurate description of the polymerization behaviour in case of the tested systems. Results clearly show important penultimate effects. At the point of knowledge, the description of the polymerization behaviour in terms of a penultimate model with depolymerization steps are suggested.
    Notizen: Für die radikalischen Copolymerisationen von α-Methylstyrol (MS) mit Methacrylnitril (MAN) sowie MS mit Acrylnitril (AN) wurden Untersuchungen zur Prüfung der in der Literatur postulierten kinetischen Modelle des „sequenzlängenunabhängigen“ bzw. „sequenzlängenabhängigen“ Terminalmodells mit Depolymerisationsschritten durchgeführt. Sie basieren auf Analysen der Sequenzverteilungen aus 13C-NMR-Spektren. Resultate von 13C-NMR-Untersuchungen an MS/MAN-Polymeren variabler Zusammensetzung werden vorgestellt. Reaktionsparameter und Gleichgewichtskonstanten wurden direkt aus den Informationen der 13C-NMR-Spektren für das Terminalmodell mit Depolymerisationsschritten in Abhängigkeit von der Reaktionstemperatur der Polymeren bestimmt. Hieraus konnten die Polymerisationsenthalpie ΔH = 26,5 ± 0,5 kJ mol-1, die Polymerisationsentropie ΔS = 95 ± 5 J mol-1 K-1 sowie die Ceilingtemperatur Tceiling = 65 ± 1°C für MS bestimmt werden. Es wurde nachgewiesen, daß im Rahmen der Terminalnäherung auch mit Berücksichtigung von Depolymerisationseinflüssen keine adäquate Beschreibung des Copolymerisationsverhaltens im Falle der untersuchten Systeme möglich ist. Vielmehr konnten als Ergebnis der Untersuchungen sowohl in Copolymeren von MS mit AN als auch mit MAN signifikante Penultimate-Effekte nachgewiesen werden. Aufbauend auf diesen Ergebnissen wird die Anwendung eines auf einer Penultimate-Näherung basierenden Modells, welches auch das Gleichgewicht in den Wachstumsreaktionen von MS berücksichtigt, zur theoretischen Vorhersage des Copolymerisationsverhaltens vorgeschlagen.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052430102
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  • 86
    Digitale Medien
    Digitale Medien
    Epoxidation of cis-cyclooctene with molecular oxygen catalyzed by magnesium oxide supported polytitazane cobalt (III) complexes (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 243 (1996), S. 69-75 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Ein auf Magnesiumoxid aufgebrachter Polytitazan-Cobalt (III)-Komplex diente als effektiver Katalysator für die Epoxidierung von cis-Cycloocten mit molekularem Sauerstoff bei Normaldruck in Gegenwart von Isobutyraldehyd als Reduktionsmittel. Nach XPS-Untersuchungen wird Cobalt (III) durch den mehrzähnigen Stickstoffliganden des Polytitazans stabilisiert. Bei 25°C beträgt der cis-Cycloocten-Umsatz nach fünf Stunden 95,2%, mit einer Selektivität von 100% für das cis-Cyclohexylenoxid. Der Katalysator Kann mindestens neun Mal ohne Aktivitätsverlust verwendet werden.
    Notizen: Magnesium oxide supported polytitazane cobalt (III) complex is demonstrated as an effective catalyst for the epoxidation of cis-cyclooctene with molecular oxygen at atmospheric pressure in the presence of isobutyraldehyde as the sacrificial reductant. XPS data show that the high-valent cobalt (III) is stabilized by the multidentate nitrogen ligand of polytitazane. The conversion of cis-cyclooctene is as high as 95.2% with 100% selectivity to the cis-cyclooctene oxide at 25°C within 5 h. The catalyst can be used at least nine times without loss of its activity.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052430106
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  • 87
    Digitale Medien
    Digitale Medien
    Phase diagram and crystallization of polycarbonate/poly-∊-caprolactone blends (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 243 (1996), S. 177-187 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Es wird über die Gleichgewichts-Schmelzpunktsdepression von Polycarbonat aus Bisphenol A (PC) in Mischungen mit Poly-∊-caprolacton (PCL) berichtet. Hierzu wird ein Modell entwickelt, das den gekrümmten Verlauf der gemessenen Hoffman-Weeks-Plots zu erklären vermag. Es berücksichtigt die Konzentrationsinhomogenitäten, die mit fortschreitender Kristallisation an der Kristallwachstumsfront entstehen. Die gelegentlich beobachtete Schmelzpunktsdepression der PCL-Komponente wird diskutiert. Der Flory-Hugginssche Wechselwirkungsparameter wird zu -0,09 berechnet; aus diesem kleinen Wert muß geschlossen werden, daß die Mischungspartner enthalpisch nur schwach wechselwirken. Der merkliche Abfall der Glastemperatur des PC nach Einmischen von PCL bewirkt eine beträchtliche Kristallisation aus der Schmelze; es können PC-Kristallinitätsgrade bis zu 25% erreicht werden.
    Notizen: It is reported on the equilibrium melting point depression of polycarbonate from bisphenol A (PC) in its blend with poly-∊-caprolactone (PCL). To this end, a model which explains the bended course of the measured Hoffman-Weeks plots is developed which takes into account the composition changes at the crystal growth front upon progressive crystallization. The occasional melting point depression of the PCL component is discussed. The calculated Flory-Huggins parameter of χ12 ≍ -0.09 indicates only weak enthalpic interactions. The remarkable drop in the glass transition temperature of PC with blending allows PC degrees of crystallinity up to 25% upon crystallization from the melt.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052430115
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  • 88
    Digitale Medien
    Digitale Medien
    Synthesis and properties of powdery hydrogels based on acrylamide, methacrylamide, and their N-substituted derivatives (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 243 (1996), S. 151-159 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Leicht vernetzte Hydrogele auf der Basis von Acrylamid, N-(1,1-Dimethyl-3-oxobutyl)acrylamid, N,N-Dimethylacrylamid, Methacrylamid, N-(2-Hydroxypropyl)-methacrylamid und N-[Tris(hydroxymethyl)methyl]methacrylamid wurden in Form von pulverigen Substanzen synthetisiert, die aus Aggregaten sehr kleiner Partikel (∼10-1 μm) bestehen. Die pulverartigen Hydrogele wurden durch Fällungspolymerisation in Aceton und Diethylether unter Verwendung von N,N′-Methylenbisacrylamid und Ethylendimethacrylat als Vernetzungsmittel synthetisiert. Es wurden die Abhängigkeiten des Quellungsgrades in Wasser, der Größe, des Aggregationsgrades und der spezifischen Oberfläche von Partikeln, und des Inhalts von wasserlöslichen Substanzen in den Hydrogelen von den Bedingungen ihrer Synthese verfolgt. Die Eignung einzelner der synthetisierten Hydrogele für die Herstellung von Silikon-kautschuk-Hydrogel-Kompositen wird diskutiert.
    Notizen: Lightly crosslinked hydrogels based on acrylamide, N-(1,1-dimethyl-3-oxobutyl)-acrylamide, N,N-dimethylacrylamide, methacrylamide, N-(2-hydroxypropyl)methacrylamide and N-[tris(hydroxymethyl)methyl]methacrylamide were synthesized in form of fine powders, consisting of aggregates of very small (∼10-1 μm) particles. The powdery hydrogels were obtained by precipitation polymerization in acetone and diethyl ether, using N,N′-methylenebisacrylamide and ethylene dimethacrylate as crosslinking agents. Dependences of water-swellability, particle size, aggregation, specific surface and content of the uncrosslinked water-soluble polymers and low-molecular-weight substances in the hydrogels on the conditions of their synthesis were studied. Suitability of particular powdery hydrogels synthesized for the preparation of silicone rubber-hydrogel composites is discussed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052430113
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  • 89
    Digitale Medien
    Digitale Medien
    Polymerization of lactams, 87Part 86 cf.21.. Block copolymers of poly(∊-caprolactam) and polybutadiene prepared by anionic polymerization. Part I: Preparation and properties (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 237 (1996), S. 123-141 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Es wurde der Einfluß der Polymerisationsbedingungen auf die Eigenschaften von Poly(∊-Caprolactam)-Polybutadien-Blockcopolymeren untersucht, die durch Reaktionsformgießen bei der anionischen ∊-Caprolactam-Polymerisation, initiiert durch das ∊-Caprolactam-Kaliumsalz, in Anwesenheit von α,ω-Dihydroxypolybutadien und Isocyanaten oder deren blockierter Derivate als Funktionalisierungsmittel hergestellt wurden.Es wurde der Einfluß des Polybutadiengehalts, dessen Molekulargewichts, des Isocyanat-Typs und der Polymerisationstemperatur auf die mechanischen Grundeigenschaften und auf die Polymerisationsgeschwindigkeit bestimmt.
    Notizen: The effect of the polymerization conditions on the properties of poly(∊-caprolactam)-polybutadiene block copolymers prepared by polymerization casting through anionic polymerization of ∊-caprolactam initiated with potassium salt of ∊-caprolactam in the presence of α,ω-dihydroxy-polybutadiene and isocyanates or their blocked derivatives as functionalizing agents was investigated.The influence of the content of telechelic polybutadiene, its molecular weight, type of diisocyanate, and polymerization temperature on the fundamental mechanical properties of the prepared materials and on the polymerization rate was evaluated.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052370107
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  • 90
    Digitale Medien
    Digitale Medien
    Synthesis of tetrahydrofuran-styrene and tetrahydrofuran-methyl methacrylate block copolymers via poly(tetrahydrofuran) with azo groups (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 238 (1996), S. 55-62 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Tetrahydrofuran (THF) wurde mit dem Initiatorsystem 4,4′-Azobis(4-cyanopentanoylchlorid)/SnCI4 kationisch polymerisiert. Das gebildete Poly(THF) mit je einer Azogruppe in der Hauptkette wurde als Initiator für die Polymerisation von Styrol (S) und Methylmethacrylat (MMA) bei 70°C eingesetzt. Die dabei entstandenen PTHF-PS-PTHF- bzw. PTHF-PMMA-Blockcopolymeren wurden mittels Fällungsfraktionierung, spektroskopischen Methoden und Viskositätsmessungen charakterisiert.
    Notizen: The cationic polymerization of tetrahydrofuran (THF) initiated by 4,4′-azobis(4-cyanopentanoyl chloride) (ACPC) and SnCI4 is described. Poly(THF) samples possessing azo gorups in the main chain thus obtained were used as initiator in the polymerization of styrene (S) and methyl methacrylate (MMA) at 70°C to yield PTHF-PS-PTHF and PTHF-PMMA block copolymers. Characterization of the block copolymers was carried out by fractional precipitation, spectroscopic methods and viscosity measurements.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052380105
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  • 91
    Digitale Medien
    Digitale Medien
    The effects of a slushing oil on the curing and degradation behavior of an oil-accommodating epoxy adhesive (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 238 (1996), S. 129-141 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die Wirkung von aliphatischem Korrosionsschutzöl auf das Aushärte- und Abbauverhalten eines ölkompatiblen Epoxidharzklebers wurde mittels Differentialkalorimetrie (DSC), Fourier-Transformations-Infrarot-Spektroskopie (FTIR) und Thermogravimetrie (TGA) untersucht. Die Ergebnisse der DSC- und FTIR-Messungen deuten darauf hin, daß die Härtungsgeschwindigkeit des untersuchten Epoxid-Systems durch das Vorhandensein des Öls nur wenig beeinflußt wird. Dennoch bestätigt das Absinken der exothermen Härtungskurve, begleitet von einer Verbreiterung des Glasübergangstemperaturbereichs, daß das Öl den Aushärtemechanismus beeinflussen kann und in der Lage ist, die Struktur des gehärteten Harzes zu verändern. Außerdem geht aus den TGA-Messungen hervor, daß die Temperaturbeständigkeit des Harzes sich in Gegenwart des Öls verschlechtert; dies wird auf Veränderungen in der Struktur und im Abbaumechanismus des Epoxid-Systems zurückgeführt.
    Notizen: The effect of aliphatic slushing oil on the curing and degradation behavior of an oil-accommodating epoxy adhesive is studied by using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The results of FTIR and DSC indicate that the curing rate of the tested epoxy system is little affected in the presence of the oil. However, the decrease of the curing exotherm accompanied with a broadening of the glass transition confirms that the oil can affect the curing mechanisms and may change the structure of the cured resin. Additionally, it is evident from the TGA results that the thermal resistance of the resin deteriorates in the presence of the oil, which is attributed to the changes in the structure and the degradation mechanism of the epoxy system.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052380112
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  • 92
    Digitale Medien
    Digitale Medien
    Electrochemical polymerization of some monomers with schiff's base structure. A voltammetric study (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 1-12 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die elektrochemische Polymerisation von Pyrrol-2-aldehyd-azin, 2,2′-[1,4-Phenylenbis(nitrilomethylidyn)]dipyrrol und 2,2′-[1,4-Biphenylylenbis(nitrilomethylidyn)]dipyrrol läuft als anodische Fällungspolymerisation ab. Monomere und Polymere wurden voltammetrisch unter Verwendung von Platin- und “Paste-carbon”-Elektroden untersucht. Die Ergebnisse stimmen mit MO-Berechnungen überein, wobei die Reaktivität der Monomeren nach Hückel abgeschätzt wurde.
    Notizen: The electrochemical polymerization of some Schiff's base-type monomers like pyrrole-2-aldehyde azine, N,N′-di(2-pyrrolylmethylene)-1,4-diaminobenzeneSystematic name: 2,2′-[1,4-phenylenebis(nitrilomethylidyne)]dipyrrole., and N,N′-di(2-pyrrolylmethylene)-4,4′-diaminobiphenylSystematic name: 2,2′-[4,4′-biphenylylenebis(nitrilomethylidyne)]dipyrrole. proceeds as a precipitating polymerization to the anodic compartment. The voltammetric study of monomers and polymers using Pt electrodes and paste-carbon electrodes were carried out. The results are in agreement with the MO calculations using the Hückel approximation for evaluating of the reactivity of the monomers.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390101
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  • 93
    Digitale Medien
    Digitale Medien
    Stereoselective polymerization of butadiene by a new dicationic nickel complex (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 33-41 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Der neuartige dikationische Komplex [dppfNi(MeCN)4][BF4]2 (dppf = 1,1′-Bis(diphenylphosphin)ferrocen) zeigte in Anwesenheit von Diethylaluminiumchlorid (AIEt2CI) hohe Aktivität für die Polymerisation von 1,3-Butadien. Reaktionsdauer, Temperatur und das Aluminium/Nickel-Verhältnis wurden auf maximale Aktivität und Selektivität optimiert. Umsätze über 90% konnten erreicht werden. Im Vergleich zu Polybutadienen, die mit anderen Nickel-Phosphin-Systemen hergestellt wurden, zeigten die synthetisierten Polybutadiene höhere cis-1,4-Anteile (〈80%) und eine geringe Bildung von 1,2-Einheiten (2%). Alle Polymeren hatten niedrige mittlere Molekulargewichte (Mw 〉 11 800).
    Notizen: The new dicationic nickel complex [dppfNi(MeCN)4][BF4]2 (dppf = 1,1′-bis(diphenylphosphino)ferrocene) in the presence of diethylaluminium chloride (AIEt2CI) exhibited high activity on the 1,3-butadiene polymerization. Reaction time, temperature and aluminium/nickel molar ratio were optimized in order to achieve maximum activity and selectivity. Conversions higher than 90% were obtained in contrast to other nickel-based systems using phosphine ligands, the resulting polybutadiene showed high cis-1,4 (〈80%) content and only small amount of 1,2-units (2%). All polymers presented low molecular weights (Mw 〉 11 800).
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390104
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  • 94
    Digitale Medien
    Digitale Medien
    Structural changes in poly(methyl methacrylate) during deep-etch X-ray synchrotron radiation lithography. Part II: Radiation effects on PMMAPart I cf.1. Dedicated to Prof. Dr. Werner Borchard on the occasion of his 60th birthday (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 79-91 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Bei der Bestrahlung von Polymethylmethacrylat (PMMA) mit Röntgensynchrotronstrahlung ändert sich die chemische Struktur des Polymeren. Die Ergebnisse der analytischen Untersuchungen dieser Arbeit weisen darauf hin, daß neben einem Abbau der Polymerketten auch einzelne Esterseitengruppen abgespalten werden. Durch die Bestrahlung entstehende Langkettenverzweigungen wurden bei PMMA nicht gefunden. Dadurch unterscheiden sich die physikalischen und chemischen Eigenschaften des bestrahlten Polymeren von denen des unbestrahlten.
    Notizen: The irradiation of poly(methyl methacrylate) changes the chemical constitution of the polymer. In addition to a decrease in molar mass further radiation-induced radical reactions cause changes in the chemical constitution of the polymer. Analysis of the reaction products shows that formation of long-chain branching can be excluded. Along with degradation of the chain lengths, ester groups in the side chains are attacked. The result is a modified polymer with a physical and chemical behaviour different from that of the starting polymer.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390108
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  • 95
    Digitale Medien
    Digitale Medien
    Synthesis of flexible polyarylates by interfacial polycondensation. Part II: Incorporation of 4,4′-thiodiphenol (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 133-149 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die Zähigkeit von Polyarylaten wurde durch den Einbau von 4,4′-Thiodiphenol und Bisphenol A, die in der wäßrigen Phase einer Grenzflächenpolykondensation vorgelegt wurden, erhöht. Die modifizierten Polyarylate besitzen leicht erniedrigte Zugfestigkeiten und Zugmoduli, aber aufgrund der Flexibilität der eingebauten Segmente stark erhöhte Izod-Schlagzähigkeiten. Darüber hinaus bleiben die guten thermischen Eigenschaften der Polyarylate nach der Modifizierung erhalten, so daß die hergestellten Materialien auch für Anwendungen mit sehr hohen Anforderungen an die thermische Belastbarkeit geeignet sind.
    Notizen: The toughness of polyarylates was improved by incorporation of 4,4′-thiodiphenol and bisphenol A, being introduced in the aqueous phase of an interfacial polycondensation reaction. The modified polyarylates possessed slightly lower tensile strength and modulus but much higher Izod impact strength due to the flexibility of the incorporated segments. In addition, the superb thermal properties typical for polyarylates were reserved in the modified polyarylate, thus assuring its broad applicability for those applications where extremely stringent criteria of thermal characteristics are required.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390112
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  • 96
    Digitale Medien
    Digitale Medien
    Le rôle des systèmes photoamorceurs dans l'efficacité de photoréticulation de l'homopolymère dicyclopentadiène acrylateNom systématique: Tricyclo[5.2.1.02.6]déc-4-en-8-yl acrylate. (DCPA) et acrylate d'éthyle (AE) et des dérivés copolymères DCPA/AE (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 169-190 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: The photocrosslinking efficiency of a series of commercial photoinitiators and multicomponent photosensitive systems on uncrosslinked acrylic matrices has been estimated. Copolymers used for this study are tricyclo[5.2.1.02,6]dec-4-en-8-yl acrylate/ethyl acrylate copolymers of variable composition (100/0, 40/60, 20/80, 0/100) synthesized in solution by a free-radical process. The irradiations were carried out at large wavelengths (λ ≥ 310 nm). Systems of benzophenone/benzoyl peroxide led to really fast crosslinking kinetics for 10 min of irradiation.
    Notizen: L'efficacité de photoréticulation de toute une série de photoamorceurs commerciaux et de systèmes photosensibles multicomposants a été évaluée sur des matrices acryliques non réticulées. Les polymères utilisés pour cette étude sont des homopolymères et des copolymères d'acrylate de dicyclopentadiène/acrylate d'éthyle de composition variable (100/0, 40/60, 20/80, 0/100) synthétisés en solution par voie radicalaire. Les irradiations ont été effectuées à des grandes longueurs d'ondes (λ ≥ 310 nm). Les systèmes benzophénone/peroxyde de benzoyle ont permis d'obtenir des cinétiques de réticulation très rapides pour des temps d'irradation de 10 min.
    Zusätzliches Material: 12 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052390115
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  • 97
    Digitale Medien
    Digitale Medien
    Ideal crosslinked-polymers and their characterization in free-radical monovinyl-divinyl copolymerizationsPoster presented at the “International Symposium on Advanced Network-Polymers, Kansai University” (ISANKU), at Kansai University, Suita, Osaka, Japan, on December 5-6, 1995. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 275-284 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The critical conditions in which the classical Flory-Stockmayer gelation theory (F-S theory) is applicable to monovinyl-divinyl copolymerizations were pursued in detail. The resulting prepolymers or precursors of ideal crosslinked-polymers were characterized as standard polymers for the discussion of network formation in free-radical monovinyl-divinyl copolymerizations. Methyl methacrylate was copolymerized with a small amount of ethylene dimethacrylate, butylene dimethacrylate or nonapropyleneglycol dimethacrylate in the presence of lauryl mercaptan, a chain transfer agent to reduce the occurrence of a thermodynamic excluded volume effect and intramolecular crosslinking as the primary and secondary factors, respectively, for the greatly delayed gelation in the free-radical monovinyl-divinyl copolymerizations and, moreover, to keep the primary chain length constant by inhibiting a gel effect. The ratio of the actual gel point to the theoretical one reached 1.1, supporting the validity of F-S theory. The resulting prepolymers were subjected to SEC-MALLS analysis to determine the molecular weights, the molecular-weight distributions and the radii of gyration; the correlations of molecular weight vs. elution volume and radius of gyration vs. molecular weight were useful for the characterization of the precursors of ideal network-polymers.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052400126
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  • 98
    Digitale Medien
    Digitale Medien
    Chemical reactions on polysaccharides, 5Part 4: Chloroacetylated derivatives of dextran, Cellul. Chem. Technol. 26 (1992) 675. Reaction of mesyl chloride with pullulan (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 241 (1996), S. 1-10 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die Reaktion von Mesylchlorid mit vernetzten Pullulan-Mikropartikeln wurde untersucht, insbesondere der Einfluß der Reaktionsbedingungen auf das Produktverhältnis Chlordeoxy-/O-Mesylpullulan. In N,N-Dimethylformamid wird vorwiegend Chlordeoxypullulan gebildet, während in Pyridin bei niedrigen Temperaturen der Mesylester das Hauptprodukt ist. In N,N-Dimethylacetamide entstehen Chlordeoxy und Mesylgruppen im Verhältnis 2:1. Durch die Einführung der Chlordeoxy- bzw. Mesylgruppen werden die Mikropartikel hydrophob.
    Notizen: The reaction of mesyl chloride with crosslinked pullulan microparticles was investigated, in particular the influence of the reaction conditions on the ratio between the two possible products chlorodeoxy or O-mesyl pullulan. It was found that in N,N-dimethylformamide the preponderent reaction product is chlorodeoxy pullulan, while in pyridine at low temperatures the main product is the mesyl ester of pullulan. In N,N-dimethylacetamide, the substituent groups are both chlorodeoxy and mesyl ones, in about 2:1 ratio. By the introduction of either chlorodeoxy or mesyl groups, the pullulan-crosslinked microparticles become hydrophobic.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052410101
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  • 99
    Digitale Medien
    Digitale Medien
    Structural analysis of poly(4-hydroxybutyl acrylate)-grafted silk fibres (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 241 (1996), S. 41-56 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Poly(4-hydroxybutylacrylat) poly(4-HBA) wurde aus wäßrigem Medium mit Ammoniumpersulfat als Initiator auf Seide (bombyx mori) aufgepfropft. Die Gewichtszunahme stieg proportional mit der Monomerkonzentration im Pfropfsystem. Der Pfropfgrad lag im Bereich von 45 bis 65%. Die Feuchtigkeitsaufnahme nahm bei einer Gewichtszunahme von 〉10% stark ab. Die mechanischen Eigenschaften der Seidenfasern zeigten mit steigender Gewichtszunahme keine wesentliche Änderung. Doppelbrechung und isotroper Brechungsindex nahmen bis zu einer Gewichtszunahme von 35% ab und blieben dann unverändert. Röntgenbeugungsdiagramme zeigten, daß die kristalline Struktur durch die Pfropfbehandlung nicht modifiziert wird. Kalorimetrische (DSC), thermomechanische (TMA) und thermogravimetrische (TG) Analysen ergaben, daß das thermische Verhalten der poly(4-HBA)-gepfropften Seidenfasern nur leicht verändert wird. Die zur Bestimmung des dynamisch-mechanischen Verhaltens der Seidenfasern durchgeführten DMA-Messungen zeigten eine Verschiebung der E′- und E″-Modulspitzen zu niedrigeren Temperaturen mit steigender Gewichtszunahme. Ablagerungen auf der Faseroberfläche der bei einem hohen Monomer/Seide-Verhältnis (〉50%) gepfropften Seide wurden mit Rasterelektronenmikroskopie nachgewiesen.
    Notizen: Poly(4-hydroxybutyl acrylate) poly(4-HBA) was graft-copolymerized onto silk fibres (bombyx mori) in aqueous medium with ammonium persulfate as initiator. The weight gain increased with increasing concentration of monomer in the grafting system. The grafting efficiency ranged from 45 to 65%. Equilibrium moisture regain decreased sharply beyond 10% weight gain. The tensile properties of the silk fibres did not change significantly as a function of the increasing weight gain. Birefringence and isotropic refractive index decreased until 35% weight gain and then remained unchanged. The X-ray diffraction patterns showed that the crystalline structure was not affected by grafting. Differential scanning calorimetry (DSC), thermomechanical (TMA), and thermogravimetric (TG) measurements showed that poly(4-HBA)-grafted silk fibres underwent only slight changes in the thermal behaviour. The dynamic mechanical measurements (DMA) exhibited a downward shift of both the storage (E′) and loss modulus peak (E″) with increasing weight gain. Scanning electron microscopy (SEM) observations showed the presence of some deposits adhering to the surface of silk fibres grafted at high monomer/silk ratio (〉50%).
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052410104
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  • 100
    Digitale Medien
    Digitale Medien
    The stability of transmembrane helices: A molecular dynamics study on the isolated helices of bacteriorhodopsin (1996)
    New York : Wiley-Blackwell
    Biopolymers 38 (1996), S. 401-422 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Bacteriorhodopsin (bR) continues to be a proven testing ground for the study of integral membrane proteins (IMPs). It is important to study the stability of the individual helices of bR, as they are postulated to exist as independently stable transmembrane helices (TMHs) and also for their utility as templates for modeling other IMPs with the postulated seven-helix bundle topology. Toward this purpose, the seven helices of bR have been studied by molecular dynamics simulation in this study. The suitability of using the backbone-dependent rotamer library of side-chain conformations arrived at from the data base of globular protein structures in the case TMHs has been tested by another set of 7 helix simulations with the side-chain orientations taken from this library. The influence of the residue's net charge on the helix stability was examined by simulating the helices III, IV, and VI (from both of the above sets of helices) with zero net charge on the side chains. The results of these 20 simulations demonstrate in general the stability of the isolated helices of bR in conformity with the two-stage hypothesis of IMP folding. However, the helices I, II, V, and VII are more stable than the other three helices. The helical nature of certain regions of III, IV, and VI are influenced by factors such as the net charge and orientation of several residues. It is seen that the residues Arg, Lys, Asp, and Glu (charged residues), and Ser, Thr, Gly, and Pro, play a crucial role in the stability of the helices of bR. The backbone-dependent rotamer library for the side chains is found to be suitable for the study of TMHs in IMP. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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