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  • 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions  (9)
  • 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy  (6)
  • Elsevier  (10)
  • AGU  (5)
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • 2005-2009  (15)
  • 2007  (15)
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  • 2005-2009  (15)
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  • 1
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    Mid-distal occurrences of the Albano Maar pyroclastic deposits and their relevance for reassessing the eruptive scenarios of the most recent activity at the Colli Albani Volcanic District, Central Italy (2007)
    Elsevier
    Details
    Publication Date: 2021-01-25
    Description: The Late Pleistocene Albano Maar hosted the most recent volcanic activity of the Colli Albani Volcanic District, represented at nearvent sections by a thick pyroclastic succession of seven units clustered in two main eruptive cycles dated at around 70–68 and 41–36 ka B.P., respectively. Recent stratigraphic investigations allowed us to recognise a pyroclastic succession comprising four eruptive units widely spread in the northeastern sectors of the Colli Albani volcano, up to 15km eastward from the Albano Maar. Integrated tephrostratigraphic, morpho-pedostratigraphic, archaeological, petrological and geochemical analyses enable us to recognise them as distal deposits of the first, third, fifth and seventh Albano Maar eruptions, enlarging significantly their previously supposed dispersion area. Further tephrostratigraphic studies in central Apennine area, allowed us to identify the Albano Maar products in Late Pleistocene deposits of several intermountain basins, extending still further the dispersion area of distal ash fallout as far as 100–120km from the vent. On the basis of the identification and the study of these previously unrecognised mid-distal Albano Maar deposits, a reappraisal of the eruptive scenarios and related energetic parameters is proposed.
    Description: Published
    Description: 160–178
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Colli Albani ; Albano ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 2
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    Seismic anisotropy reveals focused mantle flow around the Calabrian slab (Southern Italy) (2007)
    AGU
    Details
    Publication Date: 2017-04-04
    Description: SKS splitting at the Calabrian subduction zone, with delay times (δt) up to 3s, reveals the presence of a strong anisotropic fabric. Fast directions (ϕ) are oriented NNE-SSW in the Calabrian Arc (C.A.) and rotate NNW-SSE to the north following the arcuate shape of the subducting plate. We interpret the trench-parallel ϕ as local-scale mantle flow driven by the retrograde motion of the slab; the absence of trench perpendicular ϕ below the Southern Apennines (S.A.) excludes the presence of a seismically detectable return flow at its NE edge. This may be due to the relative youth and limited width of the S.A. slab tear. A possible return flow is identified farther north at the boundary of the S.A. and Central Apennines. Different and weaker anisotropy is present below the Apulian Platform (A.P.). This implies that the influence of the slab rollback in the sub-slab mantle is limited to less then 100 km from the slab.
    Description: Published
    Description: L05302
    Description: JCR Journal
    Description: open
    Keywords: shear-wave splitting, calabrian subduction zone ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    An advanced video-based system for monitoring active volcanoes (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Video surveillance systems are consolidated techniques for monitoring eruptive phenomena in volcanic areas. Along with these systems, which use standard video cameras, people working in this field sometimes make use of infrared cameras providing useful information about the thermal evolution of eruptions. Real-time analysis of the acquired frames is required, along with image storing, to analyze and classify the activity of volcanoes. Human effort and large storing capabilities are hence required to perform monitoring tasks. In this paper we present a new strategy aimed at improving the performance of video surveillance systems in terms of human-independent image processing and storing optimization. The proposed methodology is based on real-time thermo-graphic analysis of the area considered. The analysis is performed by processing images acquired with an IR camera and extracting information about meaningful volcanic events. Two software tools were developed. The first provides information about the activity being monitored and automatically adapts the image storing rate. The second tool automatically produces useful information about the eruptive activity encompassed by a selected frame sequence. The software developed includes a suitable user interface allowing for convenient management of the acquired images and easy access to information about the volcanic activity monitored.
    Description: Published
    Description: 85-91
    Description: reserved
    Keywords: Volcano monitoring ; Image processing ; Smart storing rate ; Eruption data ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
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    Separation of Qi and Qs from passive data at Mt. Vesuvius: A reappraisal of the seismic attenuation estimates (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Seismic attenuation in the area of Mt. Vesuvius is reappraised by studying more than 400 S-coda envelopes of small local VT earthquakes recorded at Mt. Vesuvius from 1996 to 2002 at the three-component stations of OVO and BKE. The purpose is to obtain a stable separate estimate of intrinsic and scattering quality factors for shear waves. We investigate in the present paper four frequency bands, centered respectively at fc = 3, 6, 12 and 18 Hz with a bandwidth of 0.6fc. Stacked coda envelopes are fit to the multiple scattering model according to the Zeng approximation in the hypothesis of constant velocity half space. Results show that the diffusion regime is a good approximation as the scattering attenuation (proportional toQ−1 S , the inverse scattering-quality factor) is much stronger than the intrinsic dissipation (proportional to Q−1 I ). Q−1 S decreases with frequency while intrinsic attenuation is much less frequency-dependent. We also fit the stacked coda envelopes at BKE to the diffusion equation solved with the boundary condition of a 2 km thick diffusive layer over a homogeneous half space. Results show that the diffusivity, D, estimated in the assumption of reflecting boundary condition is greater than that estimated in the assumption of uniform half space, whereas the diffusivity estimated with the absorbing boundary condition is close to the estimate done in the assumption of half space. OVO station shows results different from those obtained at BKE and at a group of five stations located on Mt. Vesuvius for the frequency bands centered at 12 and 18 Hz. In these two bands, scattering attenuation at OVO is comparable to the intrinsic dissipation, and is much smaller than that measured at the other stations. We interpret this anomaly as due to an effect of strong lateral heterogeneity which modifies the redistribution of the seismic energy into the coda at OVO. A comparison of the results obtained using passive data (the present data set) and the active data obtained in the same area during TOMOVES experiment by Wegler (2004) show that the diffusivity estimated with shot data during TOMOVES is smaller of a factor greater than 4. This discrepancy is interpreted as due to different earth volumes sampled by the coda waves in the two cases.
    Description: Published
    Description: 202-212
    Description: reserved
    Keywords: Scattering ; Diffusion ; Seismic attenuation ; Mt. Vesuvius ; 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)
    Type: article
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  • 5
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    New integrated geodetic monitoring system at Stromboli volcano (Italy) (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Stromboli is a composite volcano, rising about 2.5 km above the sea floor, whose top lies about 1 km above the sea level forming the northernmost island of the Aeolian Archipelago volcanic arc (Tyrrhenian Sea). On December 28th, 2002, lava flows outpoured from the northern wall of NE crater and come down in the Sciara del Fuoco (SdF), a deep depression that marks the NW flank of the volcano edifice. On December 30th, 2002, two landslides occurred on the northern part of the SdF; it moved a mass in the order of tens of millions of cubic meters both above and below the sea level. The landslide produced a tsunami that causes significant damage on the eastern cost of the island, reaching the others Aeolian Islands and the Sicilian and south Italian coasts. This event lead to the upgrade of the ground deformation monitoring system, already existing on the island; the new requirement was the real-time detection of the deformations related to potential slope failures of the SdF. To this aim, a remotely controlled monitoring system, based both on GPS and topographic techniques was planned and set up in few months. The new monitoring system allowed to continuously measure the ground deformations occurring on the SdF, by integrating both terrestrial topographic and satellite geodetic techniques. Despite this system was severely damaged during the 7-months lasting eruption, it allowed to monitor important eruptive phases. For the first time, an accurate data set about the actual mass movements of the SdF and the crater area was available. It provided data that significantly supported the Civil Protection Authorities in making decisions and constrain the hypothesis about the landslide movements and volcanic activity. After the end of the eruption, the system was reinstated in order to optimize the instruments and to set up a monitoring system aimed at measuring deformations forecasting other flank collapses.
    Description: Dipartimento Nazionale della Protezione Civile
    Description: Published
    Description: 13–31
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; Ground deformation ; Real-time monitoring ; Eruption forecasting ; Landslide forecasting ; 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::04.08. 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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  • 6
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    Tephra fallout of 2001 Etna flank eruption: Analysis of the deposit and plume dispersion (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Tephra fallout represented a major source of hazard for eastern Sicily during the 2001 eruption of Mt. Etna (Italy) between 19 July and 6 August. Long-lasting explosive activity was generated from the 2570 m vent, producing a volcanic plume up to 5 km high above sea level. The eruption caused copious lapilli and ash fallout over the volcano flanks for several days. Flight operations were cancelled at the Catania and Reggio Calabria airports; health risk and economic damage put communities living close to this active volcano on the alert. The explosive activity at the 2570 m vent had three main phases characterized by phreatomagmatic, magmatic and vulcanian explosions. In this paper, we analyze the first explosive phase between 19 and 24 July that formed a tephra deposit on the volcano's south-east flanks. Immediately after the first phase of the eruption, numerous tephra samples were collected in order to draw an isomass map, calculate physical parameters for the eruption and analyze the plume dispersion on the basis of deposit geometry. The tephra deposit shows a bilobate shape due to the change with time of both the vigour of the eruption and the wind direction and velocity that caused a higher rate of particle accumulation along two dispersal axes (SE and SSE). The total mass of tephra erupted was calculated with two different fitting methods: exponential line segments and a power law fit on the semi-logarithmic plot of mass per unit area versus , resulting in values of 1.02 109 kg and 2.31 109 kg, respectively. The whole deposit grain-size was calculated applying the Voronoi tessellation method, it shows a mode of 2 and thus indicates a high degree of magma fragmentation during the first phase of the eruption. Plume dispersal was investigated by an advection–diffusion model to reconstruct the tephra deposit. In the modelling, we took into account the variations of wind direction and velocity, and eruption intensity by dividing the explosive phase into sixteen sub-eruptions and considering the final deposit as the sum of the mass computed for each sub-eruption. Using best fit procedures, we find that the optimal agreement between computed values and field data is obtained by using the total mass calculated with the power law fit and a terminal settling velocity distribution with a particle aggregation model. The computed tephra dispersal was able to reproduce the bilobate shape of the real deposit. This work proves that advection–diffusion models can describe sedimentation processes of weak, i.e., bent-over, long-lasting plumes if the variations of wind direction and velocity, and eruptive intensity are included.
    Description: Published
    Description: 147-164
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Mt. Etna ; basaltic explosive activity ; violent strombolian eruption ; tephra deposit ; dispersal modelling ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Explosive activity at mt. etna summit craters and source modeling by using high precision continuous tilt (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We investigated the relationships between modelled strain produced by explosive activity through a volcanic conduit, observed paroxystic episodes on Mt. Etna, and high-precision continuous tilt signals recorded during such events from the tilt monitoring network. The tilt changes detected during two different explosive episodes were compared with those calculated from analytical models of ground deformation in order to constrain source properties. The July 22, 1998 subplinian explosion from Voragine crater produced small tilt changes (order of 0.5–1.5 μrad) recorded over the entire volcano edifice, implying a small storage at nearly 2.5 km below sea level. The 1998–2000 period was characterized by tens of spectacular lava fountains from the South-East crater. Very small tilt change (∼ 0.1 μrad) was recorded by a single station on the high north-eastern flank of Mt. Etna and indicated the action of a limited and shallow conduit with 1.5–1.9 km depth. These results provide a contribution to better infer the shallow plumbing system beneath Mt. Etna.
    Description: Published
    Description: 221–234
    Description: reserved
    Keywords: explosive activity ; tilt data ; volcano source modeling ; Mt. Etna ; 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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  • 8
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    Volcanic aerosol optical characteristics of Mt. Etna tropospheric (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Tropospheric volcanic plume features have been derived from airborne multispectral images collected during field measurement campaigns at the Mt. Etna volcano in June 1997, during a quiescent period, and in July 2001 during an eruptive period. Results have been obtained in terms of mapping the volcanic aerosol optical thickness (AOT), the A ˚ ngstro¨ m parameters and the water vapor content using different bands from visible to infrared. The AOT values show average values of 0.1 and 1, for quiescent and eruptive plumes, respectively, demonstrating that this geophysical parameter well indicates a major contribution of particulates in the explosive plume with respect to the quiescent one. The mapping of A ˚ ngstro¨ m parameters, in the explosive case, indicates the presence of larger particles and their distribution along the plume, while in the quiescent case indicates the particle size is dominated by small particles with an effective radius about 1 mm. Further in the quiescent case, the map of water vapor shows low values indicating that water vapor emitted condenses mainly in aerosols.
    Description: Published
    Description: 981-994
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: reserved
    Keywords: Mt. Etna; Volcanic aerosol; Mivis; Radiative transfer model ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    The Italian CMT dataset from 1977 to present (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The INGV-Harvard European-Mediterranean Regional Centroid Moment Tensor (RCMT) Catalog collects solutions routinely computed since 1997 for earthquakes with moderate magnitude (4.5 ≤ M ≤ 5.5) in the Mediterranean region. The database represents an extension to smaller magnitudes of the Harvard global CMT catalog, based on analysis of seismograms recorded at regional distance, and modeling of intermediate period surface waves. The catalog includes about 600 events, 200 of which in the Italian region. This study extends the catalog back in time, for the Italian region, as long as made possible by available digital data – i.e. since 1977 – with the same analysis and inversion method used for current seismicity. As a result, we present here 65 new moment tensors, for years between 1977 and 1997. These solutions represent 45% of the total number of events analyzed, the existing seismograms being often too scarce to allow a stable solution. The new dataset includes events in many seismic zones where moderate seismicity had previously been scarcely documented, e.g., the Po Plain, the Central to Southern Apennines and the Adriatic Sea. The complete dataset, including previously determined RCMTs and CMTs, represents the seismic deformation in the Italian area during the last 25 years.
    Description: Published
    Description: 286-303
    Description: JCR Journal
    Description: reserved
    Keywords: Seismicity ; Moment tensors ; Seismic deformation ; Italian region ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    P-wave deep velocity structure of the Southern Tyrrhenian Subduction Zone from nonlinear teleseismic traveltime tomography (2007)
    AGU
    Details
    Publication Date: 2017-04-04
    Description: A new 3-D model for the P-wave velocity structure of the Southern Tyrrhenian Subduction Zone (STSZ) is determined from nonlinear inversion of relative arrival times of teleseismic events. The data used in the imaging are the travel time residuals of both direct, P and PKPdf, and secondary pP, sP, PcP, PKPbc phases, computed with respect to the global 1-D velocity model ak135. 2308 teleseismic waveforms were collected for this study from 109 events recorded by the Italian National Seismic Network (RSNC) during 1988-1998. The velocity perturbation eld is reconstructed gradually by means an iterative sequence of linearized inversions, incorporating a 3-D minimum travel time ray tracing. The tomographic images reveal a broad highvelocity zone dominating the pattern of lateral variations beneath the Southern Tyrrhenian Sea and Calabria. This fast structure extends laterally for a maximum of 350 km, from northern Sicily to southern Campania, and vertically for at least 400 km, from the uppermost mantle down to 500 km depth. Below 350 km the geometry of the depicted slab is characterized by horizontal deflection of the subducting lithosphere towards the central Tyrrhenian basin.
    Description: Published
    Description: 3709-3712
    Description: JCR Journal
    Description: reserved
    Keywords: P-wave velocity ; teleseismic tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
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    Seismological insight into the kinematics of the 5 April 2003 vulcanian explosion at Stromboli volcano (southern Italy) (2007)
    AGU
    Details
    Publication Date: 2017-04-04
    Description: 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.
    Description: Published
    Description: L08308
    Description: reserved
    Keywords: 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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  • 12
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    Nonlinear P-wave tomography of subducted lithosphere beneath central-southern Apennines (Italy) (2007)
    AGU
    Details
    Publication Date: 2017-04-04
    Description: We present new tomographic images for the Pwave velocity structure in the upper mantle beneath centralsouthern Apennines down to 510 km depth. The model is computed by nonlinear inversion of relative arrival times of both direct and secondary teleseismic phases, handpicked from over 2800 waveforms recorded by the Italian seismic network during 1988-2000. Beneath central Apennines, the images reveal a continuous, SW-dipping high-velocity body, from 150 km down to 500 km. At shallower depths, a pronounced low-velocity zone is recognized from the uppermost mantle beneath the Apenninic belt down to 200 km below the Tyrrhenian area. This feature is proposed to affect the seismic structure of the downgoing slab, weakening its velocity signature. Beneath southern Apennines, highvelocity anomalies are reconstructed in the uppermost mantle of the Apulian foreland and below the belt in the range 100 400 km. Low-velocity regions, interpreted as due to asthenospheric upwelling, are recovered above or across the fast structures, as at the southeastern end of the Apennines where a possible complete slab breako is suggested.
    Description: Published
    Description: 4387-4390
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: P-wave tomography ; lithosphere ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 13
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    Analysis of the 2001 lava flow eruption of Mt. Etna from three-dimensional mapping (2007)
    AGU
    Details
    Publication Date: 2017-04-04
    Description: The 2001 Etna eruption was characterized by a complex temporal evolution with the opening of seven eruptive fissures, each feeding different lava flows. This work describes a method adopted to obtain the three-dimensional geometry of the whole lava flow field and for the reconstruction, based on topographic data, of the temporal evolution of the largest lava flow emitted from a vent located at 2100 m a.s.l. Preeruption and posteruption Digital Elevation Models (DEM) were extracted from vector contour maps. Comparison of the two DEMs and analysis of posteruption orthophotos allowed us to estimate flow area, thickness, and bulk volume. Additionally, the two-dimensional temporal evolution of the 2100 flow was precisely reconstructed by means of maps compiled during the eruption. These data, together with estimates of flow thickness, allowed us to evaluate emitted lava volumes and in turn the average volumetric flow rates The analysis performed in this paper provided, a total lava bulk volume of 40.1 106 m3 for the whole lava flow field, most of which emitted from the 2100 vent (21.4 106 m3). The derived effusion rate trend shows an initial period of waxing flow followed by a longer period of waning flow. This is in agreement not only with the few available effusion rate measurements performed during the eruption, but also with the theoretical model of Wadge (1981) for the temporal variation in discharge during the tapping of a pressurized source
    Description: Published
    Description: F02029
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; 2001 eruption ; three-dimensional mapping ; lava volume ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 14
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    Local tomography and focal mechanisms in the south-western Alps: Comparison if methods and tectonic implications (2007)
    Elsevier
    Details
    Publication Date: 2022-04-21
    Description: We investigate how focal solutions and hypocenter locations may depend on the ray tracing algorithm and the strategy of velocity inversion. Using arrival times from a temporary seismologal network in south-western Alps, a local earthquake tomography has been performed by Paul et al. (2001), with the method developed by Thurber (1993). Another inversion of the same data set is performed here using a different tomography code relying on a shooting paraxial method and cubic interpolation of velocities. The resulting images display the same main features, although Thurber's code appears to be more robust in regions with scarce ray coverage and strong velocity contrasts. Concerning hypocenter locations in Piemont units, one major result is the concentration of hypocenters at the boundary between the mantle wedge of the Ivrea body and the European crust. Forty-six focal mechanisms are shown that we computed using both the take-off angles in the minimum 1-D model and the 3-D velocity structures resulting from the two inversions. The sets of focal solutions are very similar, proving the reliability and the coherency of the focal solutions. The widespread extension of the core of the western Alps is confirmed whereas a few compressive soloutions are found east of the Piemont units. These results constrain the sharp change of stress tensor and evidence a decoupling of strain beneath the east of Dora Maira massif up to beneath the north of Argentera massif. On a geodynamical point of view seismicity and focal mechanism distribution are compatible with the present day models published for the western Alps, where the major feature is the lithospheric thickening (Schmid and Kissling, 2000), implying a widespread extension in the core of western Alps (Sue et al., 1999). However the existence of compressive events dealing at depth with the boundary of the Ivrea body allows to postulate that this geological structure is still tectonically active. Even if field work has not shown this so far, the Insubric line appears to extend toward the south at depth, as a blind fault, and to play a key role in the dynamis of the south-western Alps.
    Description: Published
    Description: 1-19
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: Western Alps ; Local earthquake tomography ; Focal mechanisms ; Tectonics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 15
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    A case history of paroxysmal explosion at Stromboli: Timing and dynamics of the April 5, 2003 event (2007)
    Elsevier
    Details
    Publication Date: 2023-01-16
    Description: On April 5, 2003, Stromboli volcano (Italy) produced the most violent explosion of the past 50 years. The event was exceptionally well documented thanks to the presence on the island of several scientists and a large number of instruments deployed over the preceding months to monitor the effusive eruption that began in December 2002. Integration of visual documentation, deposit features and geophysical data allowed an accurate reconstruction of the explosive event and its dynamics. The eruption consisted of a 8-min long explosive event which evolved through four phases whose timing was precisely recorded by an infrared thermometer located about 450 m from the summit crater. Phases 2 and 3 lasted 39 and 42 s, respectively. Both had an impulsive character, were responsible for ejecting almost the entire mass of the pyroclastic products. Phases 1 and 4 represented, respectively, a short-lived precursory event and a waning tale. During Phase 2, meter-sized ballistic blocks were launched with velocities of 170 m/s to altitudes of up to 1400 m above the craters. These fell on the volcano flanks and on the village of Ginostra, about 2 km distant from the vent. A vertical jet rose above the craters which developed to feed a convective plume that reached a height of up to 4 km. The calculated mass of the Phase 2 fallout deposit and mass discharge rate were 1.1–1.4×108 kg and 2.8– 3.6×106 kg/s, respectively. During Phase 3 a scoria flow deposit, with an estimated volume of 0.9–1.1×104 m3, was erupted from the same vent that fed the ongoing sustained lava flow. The average mass discharge rate for this phase was 2.5–3.1×105 kg/s. Products emitted during Phases 2 and 3 consisted of lithic and fresh magmatic material in similar proportions. The juvenile fraction consisted of a deep-originated, almost aphyric, highly vesicular pumice mingled with a shallow-derived, crystal-rich, moderately vesicular scoria. Similarities with the eruption dynamics of other historical paroxysms at Stromboli makes the April 5, 2003 explosion representative of these highly energetic events that constitute the most hazardous volcanic phenomena at Stromboli volcano.
    Description: Published
    Description: 594-606
    Description: JCR Journal
    Description: reserved
    Keywords: stromboli ; Thermal monitoring; paroxysm ; explosive dynamics ; ballistic ejecta ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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