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  • 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology  (29)
  • NONE  (22)
  • AGU  (41)
  • Istituto Nazionale di Geofisica e Vulcanologia  (6)
  • Agu  (2)
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  • 1
    Publikationsdatum: 2021-06-21
    Beschreibung: We have processed thirty Global Positioning System (GPS) campaigns carried out at Etna from 1994 to early 2001 between the last two main flank eruptions of the Mt. Etna (Sicily, Italy). This rest period allowed us to investigate the deep magma plumbing system of the Mt. Etna. The temporal dynamics of twenty-three points observed three times or more were analyzed. All the time series show a first-order linear trend during the five years period. It suggests that the volcano was continuously deformed by the action of a deep source while a discrete activity of the volcano was observed at the summit. We have interpreted the residual deformation field as the result of an major eastward motion of the eastern flank of the volcano.
    Beschreibung: Published
    Beschreibung: L02309
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 2
    Publikationsdatum: 2020-11-20
    Beschreibung: Il presente lavoro è costituito dalla raccolta sistematica delle indagini macrosismiche eseguite in occasione dei terremoti più energetici verificatisi in Sicilia orientale dal Gennaio 2002 al Dicembre 2005. Esso rappresenta l’estensione, agli anni più recenti, della compilazione effettuata per il periodo 1999-2001 [Azzaro et al., 2002], e più in generale è inserita nel contesto delle attività di pronto intervento macrosismico effettuate regolarmente in ambito regionale dal 1988. L’esecuzione di rilievi in occasione di eventi sismici significativi è una prassi ormai consolidata nelle attività di monitoraggio dell’INGV, che recentemente ha istituito a tal fine il gruppo di lavoro denominato QUEST (QUick Earthquake Survey Team, DP n° 44 del 25/02/2004). I dati raccolti assolvono ad una duplice funzione: 1) nell’immediatezza di un evento sismico, a definire il quadro degli effetti a supporto degli interventi di Protezione Civile e della Comunità Scientifica; 2) a risolvere lacune e problemi interpretativi dei terremoti del passato attraverso il confronto con gli effetti macrosismici degli eventi attuali. La raccolta sistematica di dati macrosismici anche nel caso di eventi di bassa magnitudo, che interessano estensioni areali limitate come quelle etnee, è comunque importante per l’implementazione di banche dati e cataloghi macrosismici sia a livello locale che nazionale. Nel primo caso è stato aggiornato il catalogo macrosismico dei terremoti etnei [Azzaro et al., 2000], recentemente reso disponibile anche su Internet. Nel secondo caso, la più recente versione del catalogo parametrico dei terremoti italiani [Gruppo di Lavoro CPTI, 2004] utilizzata per la redazione della nuova mappa di pericolosità sismica del territorio nazionale (Ordinanza PCM 3274 del 20/03/2003), incorpora i dati dei terremoti siciliani al di sopra della soglia del danno pubblicati in Azzaro et al. [2002, 2003]. I rilievi macrosismici di seguito riportati sono relativi a tutti i terremoti oltre la soglia del danno verificatisi nel periodo considerato, ovvero a quegli eventi che sono stati avvertiti in modo significativo dalla popolazione (Figura 1). In larga parte si tratta di eventi di area etnea che, soprattutto nel corso del 2002, hanno provocato effetti macrosismici di rilievo. Tra i terremoti regionali riportati, non è incluso il terremoto di Palermo del 2002 per il quale è disponibile uno studio specifico [Azzaro et al., 2003].
    Beschreibung: Published
    Beschreibung: 1-62
    Beschreibung: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): NONE ; Sicilia ; terremoti ; macrosismica ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
    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)
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  • 4
    Publikationsdatum: 2020-11-26
    Beschreibung: The Tindari Fault System (southern Tyrrhenian Sea, Italy) is a regional zone of brittle deformation located at the transition between ongoing contractional and extensional crustal compartments and lying above the western edge of a narrow subducting slab. Onshore structural data, an offshore seismic reflection profile, and earthquake data are analyzed to constrain the present geometry of the Tindari Fault System and its tectonic evolution since Neogene, including the present seismicity. Results show that this zone of deformation consists of a broad NNW trending system of faults including sets of right-lateral, left-lateral, and extensional faults as well as early strike-slip faults reworked under late extension. Earthquakes and other neotectonic data provide evidence that the Tindari Fault System is still active in the central and northern sectors and mostly accommodates extensional or rightlateral transtensional displacements on a diffuse array of faults. From these data, a multiphase tectonic history is inferred, including an early phase as a right-lateral strike-slip fault and a late extensional reworking under the influence of the subductionrelated processes, which have led to the formation of the Tyrrhenian back-arc basin. Within the present, regional, geodynamic context, the Tindari Fault System is interpreted as an ongoing accommodation zone between the adjacent contractional and extensional crustal compartments, these tectonic compartments relating to the complex processes of plate convergence occurring in the region. The Tindari Fault System might also be included in an incipient, oblique-extensional, transfer zone linking the ongoing contractional belts in the Calabrian-Ionian and southern Tyrrhenian compartments.
    Beschreibung: Published
    Beschreibung: TC2006
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publikationsdatum: 2021-01-11
    Beschreibung: We present a comprehensive processing tool for the real-time analysis of the source mechanism of very long period (VLP) seismic data based on waveform inversions performed in the frequency domain for a point source. A search for the source providing the best-fitting solution is conducted over a three-dimensional grid of assumed source locations, in which the Green’s functions associated with each point source are calculated by finite differences using the reciprocal relation between source and receiver. Tests performed on 62 nodes of a Linux cluster indicate that the waveform inversion and search for the best-fitting signal over 100,000 point sources require roughly 30 s of processing time for a 2-min-long record. The procedure is applied to post-processing of a data archive and to continuous automatic inversion of real-time data at Stromboli, providing insights into different modes of degassing at this volcano
    Beschreibung: Published
    Beschreibung: L04301
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publikationsdatum: 2017-04-04
    Beschreibung: Seismic activity linked to the 2002–03 Mt. Etna eruption was investigated by analyzing the Md 〉 2.3 earthquakes. The results of 3D relocation were used to compute fault plane solutions and a selected dataset was inverted to determine stress and strain tensors. The analysis revealed a complex kinematic response of the eastern flank dominated by fast stress propagation and reorientation. We hypothesize that a vertical dike intruded the southern flank, generating an extensional regime that triggered a radial intrusion in the northeast sector of the volcano. The combined effects gave rise to a rotation of the stress tensor that controlled the activation of the Pernicana fault system. The volcanic and tectonic interactions produced a second reorientation of the stress tensor, causing a structural response in the southeast lower flank. The overall result of the deformation processes observed during the eruption was an E-W extension on the eastern flank of the volcano.
    Beschreibung: Published
    Beschreibung: 4
    Beschreibung: partially_open
    Schlagwort(e): Seismology: Seismicity and seismotectonics ; Seismology: Volcano seismology ; Volcanology: Eruption mechanisms ; Volcanology: Magma migration ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 7
    Publikationsdatum: 2017-04-04
    Beschreibung: This study concerns the unstable scarp named Sciara del Fuoco (SDF) at Stromboli volcano, merging geostructural observations, live-cam records in the visible and IR bands, analysis of vertical aerial photographs, and seismic records. These are used to assess morpho-structural changes between 2002 and 2004. The onset of the lava effusion on 28 December, 2002 preceded a gravitational collapse by two days, affecting a wide area of the SDF above and below sea level. We surmise that the collapse enhanced latent instability of the scarp. The 2002–2003 lava flows had a remarkable stabilizing effect on wide portions (〉50%) of the SDF, whilst erosive phenomena continued in the zone not covered by lava. This caused unrelenting regression of the upper landslide scarp toward the summit craters in the form of rockfalls and debris flows. If the crater conduit were involved in the sliding, then a change in eruptive behavior cannot be excluded.
    Beschreibung: Published
    Beschreibung: L09304
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. 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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  • 8
    Publikationsdatum: 2017-04-04
    Beschreibung: Two unusual, highly explosive flank eruptions succeeded on Mount Etna in July August 2001 and in October 2002 to January 2003, raising the possibility of changing magmatic conditions. Here we decipher the origin and mechanisms of the second eruption from the composition and volatile (H2O, CO2, S, Cl) content of olivine-hosted melt inclusions in explosive products from its south flank vents. Our results demonstrate that powerful lava fountains and ash columns at the eruption onset were sustained by closed system ascent of a batch of primitive, volatile-rich ( 4 wt %) basaltic magma that rose from 10 km depth below sea level (bsl) and suddenly extruded through 2001 fractures maintained opened by eastward flank spreading. This magma, the most primitive for 240 years, probably represents the alkali-rich parental end-member responsible for Etna lavas’ evolution since the early 1970s. Few of it was directly extruded at the eruption onset, but its input likely pressurized the shallow plumbing system several weeks before the eruption. This latter was subsequently fed by the extrusion and degassing of larger amounts of the same, but slightly more evolved, magma that were ponding at 6–4 km bsl, in agreement with seismic data and with the lack of preeruptive SO2 accumulation above the initial depth of sulphur exsolution ( 3 km bsl). We find that while ponding, this magma was flushed and dehydrated by a CO2-rich gas phase of deeper derivation, a process that may commonly affect the plumbing system of Etna and other alkali basaltic volcanoes.
    Beschreibung: Published
    Beschreibung: B04203
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publikationsdatum: 2017-04-04
    Beschreibung: Ground-based thermal imaging is becoming an increasingly important tool for volcano surveillance, however the impact of volcanic plumes on quantitative measurements of surface temperature has not been previously evaluated. Here we use a radiative transfer model to simulate gas (primarily H2O and SO2) and aerosol absorptions over the path between a thermal camera and a heat source on Stromboli volcano, Italy. A FTIR spectrometer was used to quantify path amounts of gases likely to be encountered when making thermal measurements of the active craters. We find that when using a camera sensitive from 7.5 to 13 mm, underestimates of 400 K may be produced when viewing a source with an actual temperature of 1200 K. Cameras that operate between 3 and 5 mm are somewhat less susceptible to these errors.
    Beschreibung: Published
    Beschreibung: L14311
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 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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  • 10
    Publikationsdatum: 2017-04-04
    Beschreibung: Late on the night of 26 October 2002, a dike intrusion started suddenly at Mount Etna, producing intense explosive activity and lava effusion on the southern flank. Five to six hours afterward, a long field of eruptive fractures propagated radially along the northeastern flank of the volcano, producing marked variations at the permanent tilt network. The dike propagation velocity was inferred by the associated seismicity. We modeled the temporal evolution of the continuously recorded tilt data, both during the vertical dike propagation on the high south flank on 26 October and during the radial propagation along the northeast flank, between 27 and 28 October. The reproduction of the recorded tilt signal allowed us to describe the geometry and characteristics of the two dikes in greater detail than the previous static inversion. We deduced that the eruption was characterized by an unusual composite mechanism, clearly showing a transition from a nearly pure opening mode displacement to a mechanism characterized by an equally strong normal dip-slip component and a smaller left lateral strike-slip component. In this study we demonstrate the interaction between the final segment of the dike and a preexisting structure that was reactivated in response to the intrusion. We show that tilt and its modeling represent a powerful tool to verify and constrain dike intrusions in detail.
    Beschreibung: Published
    Beschreibung: B06404,
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    facet.materialart.
    Unbekannt
    Istituto Nazionale di Geofisica e Vulcanologia
    Publikationsdatum: 2017-04-04
    Beschreibung: Published
    Beschreibung: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Beschreibung: open
    Schlagwort(e): rock physics, geomechanics, thermo-hydro-mechanical coupling, natural hazards ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 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::04.08.05. Volcanic rocks
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book
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  • 12
    Publikationsdatum: 2017-04-04
    Beschreibung: An edited version of this paper was published by AGU. Copyright (2009) American Geophysical Union.
    Beschreibung: On multi-vents volcanoes changes in activity between different vents reflect a complex fluid-dynamics of the shallow feeding systems and are often explained numerically and experimentally in terms of conduit branches and bifurcations. We present new geophysical constraints on the shallow feeding system of Etna volcano derived from array analysis of infrasound radiated from two distinct sources, one located in the SE crater and one in the Voragine or NE crater (VNE). These two sources alternated in their behavior, with the VNE crater system radiating low amplitude background infrasound interrupted by episodes of increased infrasound radiation from the SE crater. This switching behavior suggested a branched shallow feeding system strongly controlled by the gas/magma-flux. Here, the VNE craters represented the preferential and most stable branch of degassing during stationary flux regime, while the SE crater branch activated in response to an increase in the magma/gas supply rate.
    Beschreibung: INGV-DPC V3 for the years 2005– 2007
    Beschreibung: Published
    Beschreibung: L19308
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Infrasound ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    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)
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  • 14
    Publikationsdatum: 2017-04-04
    Beschreibung: To recognize possible signals of intrusive processes leading to the last 2002–2003 flank eruption at Mt. Etna, we analyzed the spatial pattern of microseismicity between August 2001 and October 2002 and calculated 23 fault plane solutions (FPSs) for shocks with magnitude greater than 2.5. By applying the double-difference approach of Waldhauser and Ellsworth [2000] on 3D locations, we found that most of the scattered epicentral locations further collapse in roughly linear features. High-precision locations evidenced a distribution of earthquakes along two main alignments, oriented NE-SW to ENE-WSW and NW-SE, matching well both with the known tectonic and volcanic lineaments of Etna and FPSs results. Moreover, microseismicity and swarms located along the NNW-SSE volcano-genetic trend suggest, together with geodetic data and volcanological evidence that progressive magma refilling has occurred since February 2002.
    Beschreibung: Published
    Beschreibung: 1-4
    Beschreibung: partially_open
    Schlagwort(e): Seismology: Earthquake dynamics and mechanics ; Seismology: Earthquake parameters ; Seismology: Volcano seismology ; Volcanology: Eruption monitoring ; Volcanology: Magma migration. ; 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::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 15
    Publikationsdatum: 2017-04-04
    Beschreibung: Soil radon emissions have been proved as a useful tool for predicting earthquakes and volcanic eruptions and furthermore aided in determining the location of active faults. Continuous radon monitoring was carried out near Southeast Crater of Mt. Etna in September–November 1998, during a period of frequent eruptive episodes at that crater. Radon anomalies were detected when eruptive episodes and the accompanying volcanic tremor became increasingly intense: no anomalies in radon activity were observed during the first five, and weaker, eruptive episodes, whereas significant spikes in radon activity preceded the latter five episodes by ≥46 hours. This probably reflects increased gas leakage through fractures intersecting the shallow plumbing system, as gas pressure in the Southeast Crater conduit became higher with time. Radon monitoring thus might serve to better understand eruptive mechanisms and possible precursors, making further studies in this field a promising perspective.
    Beschreibung: Published
    Beschreibung: 1-4
    Beschreibung: partially_open
    Schlagwort(e): Seismology: Volcano seismology ; Structural Geology: Role of fluids ; Volcanology: Volcano monitoring ; Volcanology: Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 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
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  • 16
    Publikationsdatum: 2017-04-04
    Beschreibung: The peculiarity of the quiescent La Fossa volcano is the occurrence of ‘‘crises’’ characterized by strong increases of fumarole T and output and by chemical changes indicative of an increasing input of magmatic fluids. Several surveys carried out during a new ‘‘crisis’’ began in November 2004 indicate that the total diffuse CO2 emission for the crater area increases by one order of magnitude during crises (up to 1600 ton d 1 in December 2005). Concern exists on the possibility that these crises be related to an unrest process leading to eruption. The repetition along decades of the same gas compositional variations during crises, their temporal coincidence with increases of the local shallow seismicity, and the lack of any significant ground motion, rather suggest that they correspond to moments of increasing volatile release from a stationary magma system.
    Beschreibung: Published
    Beschreibung: L13316
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 17
    Publikationsdatum: 2017-04-04
    Beschreibung: Continuous soil radon monitoring was carried out near the Southeast Crater (SEC) of Mt. Etna during the 10-day July 2006 Strombolian-effusive eruption. This signal was compared with simultaneously acquired volcanic tremor and thermal radiance data. The onset of explosive activity and a lava fountaining episode were preceded by some hours with increases in radon soil emission by 4–5 orders of magnitude, which we interpret as precursors. Minor changes in eruptive behavior did not produce significant variations in the monitored parameters. The remarkably high radon concentrations we observed are unprecedented in the literature. We interpret peaks in radon activity as due primarily to microfracturing of uranium-bearing rock. These observations suggest that radon measurements in the summit area of Etna are strongly controlled by the state of stress within the volcano and demonstrate the usefulness of radon data acquisition before and during eruptions.
    Beschreibung: Published
    Beschreibung: L24316
    Beschreibung: reserved
    Schlagwort(e): NONE ; 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
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  • 18
    Publikationsdatum: 2017-04-04
    Beschreibung: Two swarms of microearthquakes (ML ≤ 2.2), occurred on July 2-7 and August 22, 2000 at Campi Flegrei, accompained by a ground uplift episode (4 cm) which interrupted on early March 2000 the descending trend started on 1985. Spectral analysis indicates a direct involvement of magmatic/hydrothermal fluids in the source process of the July swarm, while the August events are typical of shear failure, similar to most of the earthquakes that occurred during the last (1982-1984) bradyseismic crisis. Precise 3-D relative location applied to similar earthquakes allows for the recognition of two parallel alignments trending NE-SW at depths of 1.7 and 3.2 Km. This trend is consistent with the direction of the main focal plane obtained from fault plane solutions and evidences tensile failure in close proximity to the zone of maximum uplift as depicted by geodetic measurements. A fault weakening mechanism triggered by increasing pore pressure is invoked as the cause of these earthquakes.
    Beschreibung: Published
    Beschreibung: 2525-2528
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Campi Flegrei ; seismic swarm ; earthquakes locations ; 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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  • 19
    Publikationsdatum: 2017-04-04
    Beschreibung: A fundamental goal of volcano seismology is to understand the dynamics of active magmatic systems in order to assess eruptive behavior and the associated hazard. Imaging of magma conduits, quantification of magma transport and investigation of long-period seismic sources, together with their temporal variations, are crucial for the comprehension of eruption-triggering mechanisms. At Mt. Etna volcano, several intense episodes of tremor activity were recorded during 2007, in association with strombolian activity and/or intense fire fountaining episodes occurring from the South East Crater (SEC). The locations of the tremor sources and of the long-period seismic events are used here to constrain both the area and the depth range of magma degassing, highlighting the geometry of the shallow conduits feeding SEC. The imaged conduits consist of two connected resonating dike-like bodies, NNW-SSE and NW-SE oriented, extending from sea level to the surface. In addition, we show how tremor, long-period (LP) and very-long-period (VLP) event locations and signatures reflect pressure fluctuations in the plumbing system associated with the ascent/discharge of gas-rich magma linked to the lava fountains. The evidence here reported, also corroborated by ground deformation variations, can help develop a better prediction and early-warning system for those eruptions (effusive or explosive) that apparently manifest no clear precursors.
    Beschreibung: Supported by grants from the European Union VOLUME FP6-2004-Global-3
    Beschreibung: Published
    Beschreibung: Q12021
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): volcano plumbing system ; volcanic tremor ; LP and VLP events ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 20
    Publikationsdatum: 2017-04-04
    Beschreibung: The understanding of shallow intrusive processes during 2002–2004, as well as the causes of the volcano-tectonic seismicity, has been improved at Mt. Etna by comparing the inversion results from GPS data with accurate 3D hypocentral locations. Our findings indicate that short periods of deflation (about six months) were followed by recharging phases after the end of both the 2001 and 2002–2003 flank eruptions. During the last recharging phase (June 2003–August 2004), modeling results and seismic observations suggest a composite mechanism of re-injection of magma into the rift-zones (S and NE), similar to that leading to the 2002–2003 flank eruption, which could have triggered the summit eruption started on September 7, 2004.
    Beschreibung: Published
    Beschreibung: 1-4
    Beschreibung: partially_open
    Schlagwort(e): Volcanology: Magma migration and fragmentation ; Seismology: Earthquake interaction, forecasting, and prediction ; Seismology: Seismicity and tectonics ; Volcanology: Volcano monitoring ; Volcanology: Eruption mechanisms and flow emplacement ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 21
    Publikationsdatum: 2017-04-04
    Beschreibung: A selected dataset of 151 events, leading the July 17–August 9, 2001 lateral eruption at Mt. Etna volcano, has been analyzed for three-dimensional hypocenter locations, focal mechanisms and stress tensor inversions. The seismic pattern provided indications for two main spatial clusters of foci located along and eastwards of the 2001 Mt. Etna eruptive fractures system. The 151 fault plane solutions (mostly strike slip) were inverted for stress tensor parameters, and space variations of seismogenic stress orientations have been identified. The stress inversion results and the axi-symmetric orientation of P-axes, in the region surrounding the modeled dike, well support the evidence of a unique stress source in agreement with the ground deformation results.
    Beschreibung: Published
    Beschreibung: 1-4
    Beschreibung: partially_open
    Schlagwort(e): Seismology: Volcano seismology ; Volcanology: Eruption mechanisms ; Volcanology: Magma migration ; Volcanology: Eruption monitoring. ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 22
    Publikationsdatum: 2017-04-04
    Beschreibung: Changes in Coulomb failure stress (ΔCFS) induced by dike propagation during two flank eruptions on Mt. Etna (1981 and 2001) are calculated for the most seismically active faults on the east slope of the volcano (the right-lateral Timpe fault system, oriented NNW-SSE, and the left-lateral Pernicana fault, oriented E-W). Calculations performed using Coulomb 2.5 software indicate that intrusion of a NNW dike on the NW side of the volcano (1981 eruption) rises ΔCFS on both the Timpe and Pernicana faults. In contrast, intrusion of a N-S dike at high elevation on the south flank (2001 eruption) rises ΔCFS only on Timpe fault System. These results are compatible with the observed pattern of seismicity, but emphasize an extremely heterogeneous state of stress on the east flank of the volcano.
    Beschreibung: Published
    Beschreibung: 1-4
    Beschreibung: partially_open
    Schlagwort(e): Seismology: Earthquake interaction, forecasting, and prediction ; Seismology: Volcano seismology ; Tectonophysics: Stresses: crust and lithosphere ; Volcanology: Magma migration and fragmentation ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
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  • 23
    Publikationsdatum: 2017-04-04
    Beschreibung: Dikes provide crucial information on how magma propagates within volcanoes. Somma-Vesuvio (Italy) consists of the active Vesuvio cone, partly bordered by the older Mt. Somma edifice. Historical chronicles on the fissure eruptions in 1694–1944 are matched with an analytical solution to define the propagation path of the related dikes and to study any control of the Mt. Somma relief. The fissures always consisted of the downslope migration of vents from an open summit conduit, indicating lateral propagation as the predominant mechanism for shallow dike emplacement. No fissure emplaced beyond Mt. Somma, suggesting that its buttressing hinders the propagation of the radial dikes. An analytical solution is defined to describe the mechanism of formation of the laterally propagating dikes and to evaluate the effect of topography. The application to Somma-Vesuvio suggests that, under ordinary excess magmatic pressures, the dikes should not propagate laterally at depths 〉240–480 m below the surface, as the increased lithostatic pressure requires magmatic pressures higher than average. This implies that, when the conduit is open, the lateral emplacement of dikes is expectable on the S, Wand E slopes. The lack of fissures N of Mt. Somma is explained by its buttressing, which hinders dike propagation. Citation: Acocella, V., M. Porreca, M. Neri, E. Massimi, and M. Mattei (2006), Propagation of dikes at Vesuvio (Italy) and the effect of Mt. Somma, Geophys. Res. Lett., 33, L08301, doi:10.1029/2005GL025590.
    Beschreibung: Published
    Beschreibung: L08301
    Beschreibung: reserved
    Schlagwort(e): NONE ; 01. Atmosphere::01.01. Atmosphere::01.01.03. Pollution ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 24
    Publikationsdatum: 2017-04-04
    Beschreibung: Understanding how shallow magma is emplaced within volcanoes is crucial for hazard assessment. The 2002–2003 Stromboli eruption provides the opportunity to investigate shallow magma emplacement resulting from orthogonal feeder dikes and its possible effects. Stromboli erupted in 2002–2003, when effusive activity replaced Strombolian activity. On December 28, a NE-SW fissure propagated from the lava-filled northernmost summit crater. On December 29, a NW-SE fissure propagated north of the craters, feeding NW-SE aligned vents. On December 30, this area collapsed, reaching the sea and generating a tsunami. In mid February 2003, the NW-SE fissure became inactive, while the NE-SW effusive fissure continued until July. A model for shallow magma emplacement is proposed. The lateral propagation of a NE-SW dike from the northernmost crater was triggered. Below, a NW-SE dike, propagating from the magma-filled NE tip of the NE-SW elongated conduit, fed the NW-SE aligned vents. In February, the conduit periphery became solidified, freezing the NW-SE dike, and the transport of magma was limited to the central part, focusing its rise below the craters. This fed the NE-SW fissure until the supply decreased further (July), returning to the ordinary level sustaining Strombolian activity. Orthogonal dike emplacement followed the trajectories of the maximum (gravitational) stress s1, partly controlled by the irregular topography of the uppermost edifice. The emplacement of orthogonal dikes in a limited area is feasible at non-perfectly conical active volcanoes, where the maximum gravitational stress may show variations from a purely radial path.
    Beschreibung: Published
    Beschreibung: L17310
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 25
    Publikationsdatum: 2017-04-04
    Beschreibung: SO2 flux is widely monitored on active volcanoes as it gives a window into the hidden, subsurface magma dynamics. We present here a new approach to SO2 flux monitoring using ultraviolet imaging of the volcanic plume through carefully chosen filters to produce images of SO2 column amount. The SO2 camera heralds a breakthrough in both our ability to measure SO2 flux at unprecedented frequencies (2 Hz) and at unprecedented accuracy, thanks to the application of correlation techniques to determine wind speed directly from the images and the ability to measure the whole profile simultaneously. In this paper we detail the commercially available pieces required to construct the SO2 camera, introduce a retrieval scheme to determine SO2 amounts from the images and present results from a field campaign in November 2005 on Sakurajima volcano, Japan.
    Beschreibung: Published
    Beschreibung: L24804
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 26
    Publikationsdatum: 2017-04-04
    Beschreibung: We detect seismic wave velocity changes at Mt. Vesuvius, using doublets and the Coda Wave Interferometry method. The high sensitivity of multiply scattered coda waves to temporal changes in the medium allows us to detect velocity variation smaller than 0.4%. We use 17 doublets, some of them grouped in families of multiplets, spanning January 1996 to December 1999. Data show a systematic increase in velocity from 1996 to end- September 1999, followed by a rapid drop in velocity. This drop immediately precedes a sustained swarm of VT-type earthquakes, including the 9th October 1999 M = 3.6 event, the largest in the region since at least 1972. We propose a long term fluid pressurization followed by influx as a possible causative mechanism.
    Beschreibung: Published
    Beschreibung: L06306
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 27
    facet.materialart.
    Unbekannt
    AGU
    Publikationsdatum: 2017-04-04
    Beschreibung: NONE
    Beschreibung: Published
    Beschreibung: 385,392
    Beschreibung: open
    Schlagwort(e): NONE ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
    Publikationsdatum: 2017-04-04
    Beschreibung: On 10 September 2005 at 1711 LT (1511 UT) a loud boom was heard on the Ischia island. A clear seismic signal was also recorded by the seismic monitoring network of the Neapolitan volcanic areas (Ischia, Campi Flegrei, and Mount Vesuvius) and on a regional station (Mount Massico). On the basis of the seismic recordings and on acoustic phenomena reports, we relate this event to the atmospheric explosion (airburst) of a bolide about 15 km SW of Ischia at an elevation of about 11.5 km. The location has been obtained through nonlinear traveltime inversion in a realistic atmospheric model including wind effects. We show, using statistical estimators, how the traveltime pattern is due to both atmospheric winds and the bolide trajectory. Using the same reasoning we discard a human origin (supersonic jet or sea-air missile). In addition, we also propose a new algorithm for fast acoustic traveltime computation for a supersonic moving source.
    Beschreibung: Published
    Beschreibung: B10307
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
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  • 29
    Publikationsdatum: 2017-04-04
    Beschreibung: During the December 2005-January 2006 non-eruptive period, the tremor amplitude at Etna markedly increased and negatively correlated with the gravity signal from one of the two summit station, over 2-3 hour periods. No correlation was found with the signal from the other gravity station. We locate the tremor source by inverting the spatial distribution of seismic amplitudes. Relying on the relative position of the two stations, we define a volume within which the gravity source must lie. During the period of marked anti-correlation, the tremor sources intersect this volume in a region located 1 km S-SE of the summit craters and about 2 km beneath the surface. This finding suggests that the anti-correlation marks the activation of a joint source process, possibly related to the arrival of fresh magma and the consequent gas separation. Our study has implications for the early recognition of gas segregation processes at active volcanoes.
    Beschreibung: Published
    Beschreibung: L06305
    Beschreibung: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): volcanic tremor ; Etna volcano ; gravity changes ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 30
    Publikationsdatum: 2017-04-04
    Beschreibung: This paper presents the results of hydrogeochemical and seismological studies carried out at Mt. Vesuvius during the period June 1998 – December 2005. Hydrogeochemical data show the occurrence of slowly varying long-term variations in the total dissolved salts and bicarbonate contents of the groundwaters, accompanied by a general decline in water temperatures. The temporal distributions of air temperature and rainfall in the Vesuvius area suggest that these variations do not depend on changes in the hydrological regime. The changes in the geochemical parameters are accompanied by slight variations in both the seismicity rate and energy release. A further relationship between seismic activity and fluid discharge rate is highlighted by a particular episode that occurred in August 2005, when a soil thermal anomaly was observed a few weeks before the occurrence of a very shallow earthquake. Moment-tensor analysis of this earthquake suggests that the most plausible source mechanism is a shear faulting combined with the opening of tensile crack. This feature is often observed in volcanic areas and it is usually related to fluid-/gas-driven rock fracturing. The observed seismological, hydrological, and geochemical temporal changes are interpreted not as changes of the volcanic system, but in terms of an external forcing as identified in the variation of the regional and local stress field acting on the volcano. This study has inferences onto the evaluation of the state of activity of volcanic systems and the eventual detection of unrest phenomena.
    Beschreibung: Published
    Beschreibung: B05206
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Vesuvius ; seismicity ; fluid circulation ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
    Publikationsdatum: 2017-04-04
    Beschreibung: During local and regional earthquakes, an evident amplification of horizontal ground motion is observed at two seismological stations near the Tremestieri fault, on the southeastern flank of Mt. Etna volcano. Rotated-component spectral ratios show a narrow spectral peak around 4-Hz along a N40°E direction. A conventional polarization analysis using the eigenvectors of the covariance matrix confirms the very stable directional effect enhancing the approximately NE-SW elongation of the horizontal ground motion in the fault zone. The effect is evident during the entire seismogram and independent of source backazimuth as well as distance and depth of earthquakes. The same polarization is observed in ambient noise as well. This consistency allowed us to use microtremors for checking ground motion polarization along and across the Tremestieri fault zone with a high spatial resolution. The result is a stable polarization of horizontal motion in the entire area, interesting a broad frequency band. To check whether this ground motion property is recurrent and understand a possible relationship with fault strike, faulting style, or orientation of fractures, ambient noise was recorded on other mapped faults of the Mt. Etna area, the Moscarello, Acicatena and Pernicana faults. The latter, in particular, is characterized by different strike and faulting style. A systematic tendency of ambient noise to be polarized is found in all of the faults. A picture emerges where normal faults of the eastern flank show a E-W to NE-SW polarization that changes on the Pernicana fault, which develops approximately E-W and is characterized by a prevailing NW-SE to NS polarization. Directions of polarization were never parallel to the fault strike. Moreover, polarization persists too far away from the fault trace, excluding an effect limited to a narrow low velocity zone hosted between harder wall rocks. Both these observations rule out an interpretation in terms of fault-trapped waves. The cause of observed polarizations will be the subject of future studies. However, the consistency with recent results of velocity anisotropy in a part of the investigated area suggests a possible role of attenuation anisotropy on horizontal amplitude variations versus azimuth.
    Beschreibung: Published
    Beschreibung: B10306
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): polarization ; fault zones ; Etna volcano ; microtremors ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
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  • 32
    Publikationsdatum: 2017-04-04
    Beschreibung: Five three-component broadband ocean bottom seismometers (OBSs) were deployed on the seafloor around the Aeolian Islands (Southern Tyrrhenian Sea). By comparing OBSs digital seismograms, we found a low-frequency seismicity recorded only at OBS05, the nearest seafloor station to Stromboli volcano. This seismicity appears in the form of a continuous seismic signal (tremor-like-signal) as well as a considerable number of shock-like events. We focused on recordings from OBS05 to verify their correlation with Stromboli volcanic activity. From the spectral analysis, we observed low-frequency events (LP events), superposed upon the continuous background noise (tremor). LP events and tremor, showing similar energy fluctuations and frequency content, appear to be produced by the same dynamic processes. We interpret this low-frequency seismicity as probably originating from a continuous uprising of gas bubbles from the deeper part of the Stromboli magmatic column. This could highlight the existence of a deeper source for low-frequency seismicity.
    Beschreibung: Published
    Beschreibung: L04305
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Volcano-seismology ; low-frequency events ; tremor ; OBSs ; Stromboli (Southern Tyrrhenian Sea) ; 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
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  • 33
    Publikationsdatum: 2017-04-03
    Beschreibung: A lava emission started at Mt. Etna, Italy, on 7 September, 2004. Neither earthquake seismicity heralded or accompanied the opening of the fracture field from which the lava poured out, nor volcanic tremor changed in amplitude and frequency content at the onset of the effusive activity. To highlight long-term changes, we propose a method for the location of the tremor source based on a 3D grid search, using the amplitude decay of the seismic signal, from January to November 2004. We find the centroid of the tremor source within a zone close to and partially overlapped with the summit craters (pre-effusive phase), which extended up to 2 km south of them (effusive phase). The depths are of between 1698 and 2387 m a.s.l. We hypothesize the lava effusion stemmed from a degassed magma body, although we find evidence of temporary magma overpressure conditions, such as those documented on 25 September.
    Beschreibung: Published
    Beschreibung: L09304
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 34
    Publikationsdatum: 2017-04-04
    Beschreibung: After the end of the 2002–2003 eruption, Mount Etna activity was characterized only by gentle degassing at the summit craters and some earthquake swarms. Suddenly, an eruption started on 7 September 2004 in complete absence of summit crater volcanic activity, seismicity or seismic tremor, and ground deformation. This is the first time that magma poured out passively without preeruptive and coeruptive volcanic and/or geophysical phenomena. The primary key to understanding this event is represented by the ground deformation pattern recorded through GPS measurements during the year before the eruption. The ground deformation shows inflation superimposed by a predominant eastward movement of the eastern sector at a rate never observed before in a noneruptive period. The images from satellite radar interferometry confirmed this pattern. The deformation field clearly shows that the maximum tension in the eastern sector of the volcano caused the opening of the eruptive fracture which favored the silent pouring out of already resident magma.
    Beschreibung: Published
    Beschreibung: B12207
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 35
    Publikationsdatum: 2017-04-04
    Beschreibung: A thermal modeling of the Vesuvius is presented, based on its magmatic and volcanic history. A 2D numerical scheme has been developed to evaluate the heat transfer inside and around a magma body, the latent heat of crystallization and the inputs of magma from the asthenosphere to a crustal reservoir. Assuming a ratio 〉1 between velocities of magma ascending in the conduit and magma laterally displaced in the reservoir, the results indicate that, after 40 ka, the reservoir is vertically thermally zoned. As a consequence it hosts magma batches that can individually differentiate, mix and be contaminated by the crust, and produce the spectrum of isotopic compositions of the Vesuvian products. The thermal model reproduces the geothermal gradient and the brittle-ductile transition (250– 300 C) at 6 km of depth (the maximum depth of earthquake foci) only after 0.5–1 Ma, implying a long lived magma chamber below the volcano.
    Beschreibung: Published
    Beschreibung: L17302
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    Publikationsdatum: 2017-04-04
    Beschreibung: We model the location, geometry and density of the source of the recent geological unrest at Campi Flegrei caldera (Italy) by inverting levelling, trilateration and gravity measurements collected between 1980 and 1995. The best fitting source for the 1980–84 inflation is a horizontal penny-shaped crack with a density 142 to 1115 kg/m3. The source best fitting the deflation period (1990–95) is a vertical spheroid with density between 902 and 1015 kg/m3. These results exclude the intrusion of magma, and indicate the migration of fluid to and from the caldera hydrothermal system as the cause of ground deformation and consequent unrest.
    Beschreibung: Published
    Beschreibung: L01307
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
    Publikationsdatum: 2017-04-04
    Beschreibung: On 5 April 2003 at 07:13 GMT (09:13 local time) a violent vulcanian explosion occurred at Stromboli volcano. At the time of the event an eruptive crisis was ongoing at the volcano with a lava flow outpouring along the Sciara del Fuoco flank. The seismic signals related to the event were recorded by 8 permanent broadband stations and gives information about the eruption kinematics. An ultra-longperiod signal (period 〉 20 s), that we interpret as the effect of the ground tilt on the broadband sensors, starts about 4 min before and terminates about 1 min after the explosion. On the basis of the radial pattern of tilt directions we conclude that this signal is the effect of the deformation of the volcanic edifice, due to the rapid rising of a batch of magma, its ejection and the magma column readjustment. About 1 min before the explosion we observe an high frequency signal (period 〈 0.1 s) that we believe to be related to the vesiculation of the rising batch of gas-rich magma. At 07:13:35 GMT a powerful very-long-period signal (period 2 20 s), marking the onset of the explosive fragmentation, is recorded. This is confirmed by a blast wave following few seconds later. The remaining seismic signal (more than 3 min), shows an higher frequency content being related only to the fall of ballistic ejecta and to landslides along Sciara del Fuoco.We propose the implementation of an early warning system for the short-term forecast of such explosions, based on the real-time automatic detection of the tilt signals preceding such events.
    Beschreibung: Published
    Beschreibung: L08308
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
    Publikationsdatum: 2017-04-03
    Beschreibung: The relationship between permeability and porosity is reviewed and investigated. The classical Kozeny-Carman approach and a fractal pore-space geometry assumption are used to derive a new permeability-porosity equation. The equation contains only two fitting parameters: a Kozeny coefficient and a fractal exponent. The strongest features of the model are related to its simplicity and its capability to describe measured permeability values of different non-granular porous media better than other models.
    Beschreibung: Published
    Beschreibung: L02318
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 39
    Publikationsdatum: 2017-04-04
    Beschreibung: The goal of this paper is to yield physical constrains on the nature and evolution of a seismic swarm by means of a quantitative stochastic modeling of earthquakes occurrence. With this purpose, we fit different stationary and nonstationary stochastic ETAS models to the Izu Islands seismic swarm occurred in 2000. We find that a nonstationary model with background activity and p-value varying through time describes the observations better than other simpler ETAS models. The coherent fluctuations of these parameters and of the spatio-temporal earthquake distribution are interpreted in terms of a magma/fluids source process that evolves through outbursts of activity superimposed to low frequency variations. The results obtained suggest that suitable nonstationary ETAS modeling can be very useful to characterize the nature of the swarm source, and it may provide the basis to build a quantitative tool for tracking in almost real-time the evolution of a magma/fluids source.
    Beschreibung: Published
    Beschreibung: L07310
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): volcanic seismic ; Izu Islands swarm ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 40
    Publikationsdatum: 2017-04-04
    Beschreibung: In the text
    Beschreibung: Published
    Beschreibung: 1545-1548
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): anisotropy ; eruptive fracture ; 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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  • 41
    Publikationsdatum: 2017-04-04
    Beschreibung: The typical earthquakes occurring at Mt. Vesuvius are Volcano-Tectonic. On July 20, 2003, an unusual earthquake with low and narrow frequency content was detected. The seismograms presented an emergent onset and a nearly monochromatic spectrum at all stations of the Osservatorio Vesuviano(Istituto Nazionale di Geofisica e Vulcanologia) seismic network. The event was located at about 4 km b.s.l. close to the crater axis and an equivalent duration magnitude of 0.6 was estimated. The nature of this event was investigated by comparing its features with those of two typical Volcano-Tectonic earthquakes occurred inside the same source volume. We compared the spectral content calculating the spectrograms and the coda patterns using the Hilbert Transform. A Seismic Moment Tensor inversion was performed on the low frequency earthquake. The focal mechanisms for the two Volcano-Tectonic earthquakes were estimated with a classical technique and resulted compatible with the stress field acting on the volcano. Taking into account the clear differences with the typical Volcano-Tectonic events as well as the peculiarities retrieved from our analyses (monochromatic, low frequency spectral content, and sustained coda) and also some geochemical observations, we classify the unusual low frequency seismic event detected at Mt. Vesuvius as Long Period earthquake and propose that its origin could be linked to a pressure drop in the deep hydrothermal system.
    Beschreibung: Published
    Beschreibung: S0440
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Volcano monitoring ; Volcanic event classification ; Long Period earthquake ; Signal analysis ; Hydrothermal system ; 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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  • 42
    Publikationsdatum: 2017-04-04
    Beschreibung: We have analyzed the recent seismicity of Mt. Vesuvius, with particular emphasis on the period 1999-2012. Since 1972 continuous observations with electromagnetic seismometers allowed the compilation of a detailed earthquake catalogue for the station OVO. Furthermore since 1999 another, more complete, catalogue for the station BKE, closer to the crater, is available. The Gutenberg-Richter distribution of magnitudes shows a temporal decrease of the b-value since 1985, with current values close to 1.0. The temporal pattern of the strain release shows a non-stationary behavior with periods of increased release rates (as in 1989-1990, 1995-1996 and 1999-2000). The spatial distribution of the seismicity consists in two main seismogenic volumes, one with hypocenters clustered below the Mt. Vesuvius crater at depths mostly between 1-6 km, and another with hypocenters clustered within the Gran Cono volcanic edifice, with depths above the sea level. We compare the statistical properties of the seismicity occurring within these two volumes and their spatial and temporal patterns. Moreover we analyze the statistical distribution of focal mechanisms for each volume. Our results point to gravity-induced stresses as the source of the shallow seismicity and of a combined effect of crustal heterogeneities, regional stress and hydrothermal dynamics for the deeper seismicity. Finally we discuss possible future developments of the seismic monitoring system in the light of the past and current seismicity.
    Beschreibung: Published
    Beschreibung: S0442
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Mt. Vesuvius ; seismological monitoring ; 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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  • 43
    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)
    Materialart: article
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  • 44
    facet.materialart.
    Unbekannt
    Istituto Nazionale di Geofisica e Vulcanologia
    Publikationsdatum: 2017-04-04
    Beschreibung: One of the main issues in seismic monitoring of active volcanic areas is the accurate location of earthquake hypocenters. Volcano-tectonic seismicity is often characterized by small magnitude swarms, recorded by few seismic stations with a high picking uncertainty. Sometimes events lacks clear S-wave arrivals, due to the nature of some volcanic sources. All these features, together with the complex crustal structure of volcanoes, makes the earthquake location problem critical in such areas. One of the most important effort for improving the quality of hypocenter location is the use of realistic 3D velocity models. In the last 10 years, several scientific papers proposed 2D and 3D velocity models for Mt. Vesuvius, Campi Flegrei and the Gulf of Naples. They comes from both active seismic data (VESUVIO 94, TOMOVES 96, MAREVES 97 and SERAPIS 2001 experiments) and from local earthquake tomography. In this report we propose a global unified velocity model spanning from Ischia island to Appennine Mts. that allows us to locate earthquakes in the Neapolitan volcanic areas and in the Gulf of Naples. This model comes from a weighted averaging of 5 tomographic velocity models and a background regional model. Most of the model provides only P-wave velocities, only 2 models, obtained through local earthquake tomography at Mt. Vesuvius and Campi Flegrei also gives a S-wave velocity estimate. We show the difference between this new model and the previous 1D models adopted for routine locations at INGV-Osservatorio Vesuviano. We also relocate some events, using non-linear techniques showing differences in hypocenter position from previous locations and the improvement in final traveltime residuals and location uncertainties.
    Beschreibung: Published
    Beschreibung: 375-390
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: open
    Schlagwort(e): Volcano-tectonic seismicity ; 3D velocity model ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book chapter
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  • 45
    Publikationsdatum: 2017-04-04
    Beschreibung: The computing techniques currently available for the seismic monitoring allow advanced analysis. However, the correct event classification remains a critical aspect for the reliability of real time automatic analysis. Among the existing methods, neural networks may be considered efficient tools for detection and discrimination, and may be integrated into intelligent systems for the automatic classification of seismic events. In this work we apply an unsupervised technique for analysis and classification of seismic signals recorded in the Mt. Vesuvius area in order to improve the automatic event detection. The examined dataset contains about 1500 records divided into four typologies of events: earthquakes, landslides, artificial explosions, and “other” (any other signals not included in the previous classes). First, the Linear Predictive Coding (LPC) and a waveform parametrization have been applied to achieve a significant and compact data encoding. Then, the clustering is obtained using a Self-Organizing Map (SOM) neural network which does not require an a-priori classification of the seismic signals, groups those with similar structures, providing a simple framework for understanding the relationships between them. The resulting SOM map is separated into different areas, each one containing the events of a defined type. This means that the SOM discriminates well the four classes of seismic signals. Moreover, the system will classify a new input pattern depending on its position on the SOM map. The proposed approach can be an efficient instrument for the real time automatic analysis of seismic data, especially in the case of possible volcanic unrest.
    Beschreibung: Published
    Beschreibung: S0446
    Beschreibung: 5V. Sorveglianza vulcanica ed emergenze
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Mt. Vesuvius ; Neural analysis ; 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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  • 46
    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)
    Materialart: article
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  • 47
    Publikationsdatum: 2019-03-05
    Beschreibung: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.
    Beschreibung: Passive high‐resolution attenuation tomography is used here to image the geological structure in the first upper 4 km of the shallow crust beneath the Campi Flegrei caldera, southern Italy. The inverse Q was estimated for each source‐receiver path using the coda‐normalization method (S‐waves) and the slope decay method (P‐waves and S‐waves). Inversion was performed using a multi‐resolution method, which ensures a minimum cell‐size resolution of 500 m. The study of the resolution matrix as well as the synthetic tests guarantee an optimal reproduction of the input anomalies in the center of the caldera, between 0 and 3.5 km in depth. High attenuation vertical structures are connected at the surface with the main volcanological features (e.g., the Solfatara and Mofete fumarole fields), and depict vertical Q contrast imaging important geological structures, such as the La Starza fault. These high attenuation volumes extend between the surface and a depth of about 3 km, where a hard rock layer is imaged by the sharp contrast of the quality factors. The retrieved image of the Campi Flegrei has been jointly interpreted taking into account evidence from seismological, geological, volcanological and geochemical investigations. This analysis has allowed an unprecedented view of the feeding systems in this area, and in particular it recognizes the vertically extending, high attenuation structures that correspond to gas or fluid reservoirs beneath Pozzuoli‐Solfatara, Solfatara, Mofete‐Mt. Nuovo and Agnano. This high‐attenuation system is possibly connected with the magma sill revealed at about 7 km in depth by passive travel‐time tomography.
    Beschreibung: Published
    Beschreibung: B09312
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Campi Flegrei ; gas ; 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 ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 48
    Publikationsdatum: 2017-04-04
    Beschreibung: We study the seismic wavefield and the statistical properties of the Stromboli volcano explosions preceding and during 2002-2003 crisis. We analyze the recordings of a three-component seismometer operating since 23/05/2002 to 30/01/2003, 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 timestable independent oscillations peaked at 1.1, 1.8, and 2.5 Hz, respectively, with radial and shallow polarization indicating a stable source mechanism. Energy of the explosions is log-normally distributed, except during a twomonth time interval before the crisis when it shows also a higher mean value. The inter-occurrence time distributions display an homogeneous poissonian behaviour with a mean inter-time 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 systems that induces a deep gas slug nucleation and the excitation of low frequencies.
    Beschreibung: In press
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Stromboli ; explosion-quakes ; 2002-2003 eruptive crisis ; 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
    facet.materialart.
    Unbekannt
    AGU
    In:  Citation: Tedesco, D., et al. (2007), Cooperation on Congo Volcanic and Environmental Risks, Eos Trans. AGU, 88(16), 177.
    Publikationsdatum: 2024-05-09
    Beschreibung: Article
    Beschreibung: On 17 January 2002, the Nyiragongo volcano (1.52°S, 29.25°E, 3469 meters above sea level), located about 18 kilometers north of Lake Kivu in the Democratic Republic of Congo, erupted, releasing a volume of 14-34 million cubic meters of lava. Lava flows originated from north-south oriented fractures that rapidly developed along the southern flank of the volcano. Two lava flows divided the nearby city of Goma (~500,000 people) into two parts, forcing a rapid exodus of the population into Rwanda. One of these lava flows ran into Lake Kivu, encroaching 60 meters below lake level with a submerged lava volume of 1 million cubic meters. About 15% of the town was directly affected, leaving approximately 120,000 people homeless. At least 170 people died as a direct consequence of the eruption
    Beschreibung: American Geophysical Union
    Beschreibung: Published
    Beschreibung: 177-188
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: N/A or not JCR
    Beschreibung: reserved
    Schlagwort(e): Volcanology ; Telemetered Seismic Network ; Effusive volcanism ; Volcanology ; Experimental volcanism ; 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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