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Analysis of the 9 September 1998 Mw 5.6 Mercure earthquake sequence (Southern Apennines, Italy): A multidisciplinary approach (2012)

Brozzetti, F. ; Lavecchia, G. ; Mancini, G. ; [weitere]

Elsevier

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Publikationsdatum: 2017-04-04

Beschreibung: The Mercure earthquake (Mw 5.6) of September 9, 1998 and the associated aftershocks occurred in a small Pleistocene–Holocene continental basin of the Southern Apennines, in a region of low instrumental and moderate historical seismicity. Seismological, photogeological and ﬁeld survey data were analyzed and integrated in order to identify the likely seismogenic structure, to depict its 3-D geometry and kinematics and to provide further constraints to the seismogenic potential of the rupture processes in the study area. The mainshock occurred at the NW edge of the seismic sequence (40.03°N and 15.95°) at a depth of 10.5± 1.5 km. The aftershocks volume was determined from the relocation of about 200 events (1.1=Ml=3.9) registered by local networks from September 10 to October 12, 1998. The relocation procedure was based on choosing P and S waves for all the events and the deﬁnition of ten 9-layers velocity models appropriate for the different stations. The kinematics of the seismogenic deformation was deﬁned through the computation of 36 well-constrained focal mechanisms. The seismological and geological stress tensors were determined through inversion of focal mechanisms and fault slip data. Both of them resulted in the tensional type, with ENE–WSW and NE–SW trending σ3 axis, respectively. The map and the section distribution of the aftershocks sequence depicts an average NW–SE striking and 60° SW-dipping seismogenic volume. Most of the events (80%) were located at depths between 3 and 8 km in the footwall of the Mercure basin (MBB) boundary fault but along the possible down-dip continuation of a previously unidentiﬁed, N120°E striking and WSW-dipping, Holocene normal fault alignment, which extends from Castello Seluci to Piana Perretti and Timpa della Manca (CPST fault). A small percentage of events (10%) were located at depths between 10 and 12 km where the CPST seismogenic fault may detach. The reconstructed rupture area (RA) of the Mercure 1998 earthquake has an along-strike length (L) of about 9 km and a down-dip width (W) of about 9 km, yielding a total area of approximately 81 km2 . On the other hand, the L and W dimension of the entire individual seismogenic structure identiﬁed as responsible for the earthquake, e.g. the CPST fault, are about 19 and 12 km, respectively, with a consequent RA of about 230 km2 . This may imply a maximum magnitude (Mw) equal to 6.3 which lead us to compare the Mercure area, in terms of seismogenic hazard, to the adjacent Pollino-Castrovillari area where strong paleoseismological events are documented.

Beschreibung: Published

Beschreibung: 210–225

Beschreibung: 3.2. Tettonica attiva

Beschreibung: JCR Journal

Beschreibung: reserved

Schlagwort(e): Southern Apennines ; Stress-distribution ; Earthquake location ; Seismotectonics ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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Spatial vent opening probability map of Etna volcano (Sicily, Italy) (2012)

Cappello, A. ; Neri, M. ; Acocella, V. ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2017-04-04

Beschreibung: We produce a spatial probability map of vent opening (susceptibility map) at Etna, using a statistical analysis of structural features of flank eruptions of the last 2 ky. We exploit a detailed knowledge of the volcano structures, including the modalities of shallow magma transfer deriving from dike and dike-fed fissure eruptions analysis on historical eruptions. Assuming the location of future vents will have the same causal factors as the past eruptions, we converted the geological and structural data in distinct and weighted probability density functions, which were included in a non-homogeneous Poisson process to obtain the susceptibility map. The highest probability of new eruptive vents opening falls within a N-S aligned area passing through the Summit Craters down to about 2,000 ma.s.l. on the southern flank. Other zones of high probability follow the North-East, East-North-East, West, and South Rifts, the latter reaching low altitudes (∼400 m). Less susceptible areas are found around the faults cutting the upper portions of Etna, including the western portion of the Pernicana fault and the northern extent of the Ragalna fault. This structuralbased susceptibility map is a crucial step in forecasting lava flow hazards at Etna, providing a support tool for decision makers.

Beschreibung: This study was performed with the financial support from the V3-LAVA project (DPC-INGV 2007–2009 contract).

Beschreibung: Published

Beschreibung: 2083–2094

Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani

Beschreibung: 3.2. Tettonica attiva

Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi

Beschreibung: 3.6. Fisica del vulcanismo

Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica

Beschreibung: JCR Journal

Beschreibung: restricted

Schlagwort(e): Flank eruption ; Dike ; Volcano structure ; Susceptibility map ; Spatial clustering ; Back analysis ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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Gas and aerosol emissions from Villarrica volcano, Chile (2012)

Sawyer, G. M. ; Salerno, G. G. ; Le Blond, J. S. ; [weitere]

Elsevier

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Publikationsdatum: 2017-04-04

Beschreibung: Here we report results from a multidisciplinary field campaign at Villarrica volcano, Chile, in March 2009. A range of direct sampling and remote sensing techniqueswas employed to assess gas and aerosol emissions from the volcano, and extend the time series of measurements that have been made during recent years. Airborne traverses beneath the plume with an ultraviolet spectrometer yielded an average SO2 flux of 3.7 kg s−1. This value is similar to previous measurements made at Villarrica during periods of quiescent activity. The composition of the plume was measured at the crater rim using electrochemical sensors and, for the first time, open-path Fourier transforminfrared spectroscopy, yielding a composition of 90.5 mol% H2O, 5.7% CO2, 2.6%SO2, 0.9% HCl, 0.3% HF and b0.01% H2S. Comparison with previous gas measurements made between 2000 and 2004 shows a correlation between increased SO2/HCl ratios and periods of increased activity. Base-treated filter packs were also employed during our campaign, yielding molar ratios of HBr/SO2=1.1×10−4, HI/SO2=1.4×10−5 and HNO3/SO2=1.1×10−3 in the gas phase. Our data represent the most comprehensive gas inventory at Villarrica to date, and the first evaluation of HBr and HI emissions from a South American volcano. Sun photometry of the plume showed the near-source aerosol size distributions were bimodal with maxima at b0.1 and ~1 μm. These findings are consistent with results from analyses in 2003. Electron microscope analysis of particulatematter collected on filters showed an abundance of sphericalmicron-sized particles that are rich in Si, Mg and Al. Non-spherical, S-rich particles were also observed.

Beschreibung: Antofagasta plc via the University of Cambridge Centre for Latin American Studies, NERC Field Spectroscopy Facility, NERC projectNE/F004222/1, “Volgaspec” projectANR-06-CATT-012-01 and from the NOVAC project. Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento di Protezione Civile-Regione Sicilia. Christ's College, University of Cambridge, NERC IKIMP project, (NE/G001219/1) and NERC grantNE/G01700X/1 for financial support. NERC National Centre for EarthObservation (“Dynamic Earth and geohazards”)

Beschreibung: Published

Beschreibung: 62-75

Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive

Beschreibung: JCR Journal

Beschreibung: reserved

Schlagwort(e): Villarrica ; FTIR ; SO2 flux ; DOAS ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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Mapping and DOWNFLOW simulation of recent lava flow fields at Mount Etna (2012)

Tarquini, S. ; Favalli, M.

Elsevier

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Publikationsdatum: 2017-04-04

Beschreibung: In recent years, progress in geographic information systems (GIS) and remote sensing techniques have allowed the mapping and studying of lava flows in unprecedented detail. A composite GIS technique is introduced to obtain high resolution boundaries of lava flow fields. This technique is mainly based on the processing of LIDAR-derived maps and digital elevation models (DEMs). The probabilistic code DOWNFLOW is then used to simulate eight large flow fields formed at Mount Etna in the last 25 years. Thanks to the collection of 6 DEMs representing Mount Etna at different times from 1986 to 2007, simulated outputs are obtained by running the DOWNFLOW code over pre-emplacement topographies. Simulation outputs are compared with the boundaries of the actual flow fields obtained here or derived from the existing literature. Although the selected fields formed in accordance with different emplacement mechanisms, flowed on different zones of the volcano over different topographies and were fed by different lava supplies of different durations, DOWNFLOW yields results close to the actual flow fields in all the cases considered. This outcome is noteworthy because DOWNFLOW has been applied by adopting a default calibration, without any specific tuning for the new cases considered here. This extensive testing proves that, if the pre-emplacement topography is available, DOWNFLOW yields a realistic simulation of a future lava flow based solely on a knowledge of the vent position. In comparison with deterministic codes, which require accurate knowledge of a large number of input parameters, DOWNFLOW turns out to be simple, fast and undemanding, proving to be ideal for systematic hazard and risk analyses.

Beschreibung: Published

Beschreibung: 27-39

Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica

Beschreibung: 5.5. TTC - Sistema Informativo Territoriale

Beschreibung: JCR Journal

Beschreibung: reserved

Schlagwort(e): LIDAR ; lava flow field ; lava flow simulation ; Digital elevation model ; Mount Etna ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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Texture analysis of volcanic rock samples: Quantitative study of crystals and vesicles shape preferred orientation from X-ray microtomography data (2012)

Voltolini, M. ; Zandomeneghi, D. ; Mancini, L. ; [weitere]

Elsevier

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Publikationsdatum: 2017-04-04

Beschreibung: In the texture analysis of volcanic rocks, the preferred orientation of the constituents can provide useful information for the interpretation of the processes involved in the rock formation. We present here a new data analysis technique, based on X-ray microtomography measurements and on shape preferred orientation analysis, to obtain the orientation distribution functions of the constituents of volcanic rocks. This procedure proved to be very suitable for volcanic samples, where diffraction-based techniques, developed for crystallographic preferred orientation studies, are of limited utilization, in addition to the fact that they cannot provide any information about vesicles or bubbles. Moreover the analysis performed directly in three dimensions (3D) overcomes the problems that usually occur when employing stereological methods for the analysis of the images obtained via microscopy-based techniques. In this study, two scoriae (from Stromboli and Etna) and a tube pumice (from Campi Flegrei) were measured via X-ray microtomography and then the resulting volumes were analyzed following the proposed procedure. Results highlight little preferred orientation for the vesicles in the two scoria samples, whereas the pumice shows a marked preferred orientation. Crystals (also divided by mineral species) were taken into account as well and in the two scoria samples there is no crystal preferred orientation, in contrast with the pumice, where crystal preferred orientation features are very similar to the ones found for the vesicles. Overall we found strong differences in preferred orientation: weak for vesicles in scoriae, showing an axial symmetry with the axis parallel to the elongation axis of the sample, and a stronger and more complex orientation texture in the pumice sample for both crystals and vesicles. The promising results obtained suggest that this procedure is potentially very useful for the analysis of preferred orientation in volcanic rocks and geomaterials in general.

Beschreibung: Published

Beschreibung: 83-95

Beschreibung: 2.3. TTC - Laboratori di chimica e fisica delle rocce

Beschreibung: JCR Journal

Beschreibung: reserved

Schlagwort(e): X-ray computed microtomography ; preferred orientation ; texture analysis ; volcanic scoria ; synchrotron X-rays ; pumice ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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Reconstruction of SO2 flux emission chronology from space-based measurements (2012)

Merucci, L. ; Burton, M. ; Corradini, S. ; [weitere]

Elsevier

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Publikationsdatum: 2017-04-04

Beschreibung: Infrared satellite images measured with the MODIS instrument of the volcanic plume produced during the 2006 eruption of Mt. Etna were analysed to produce maps of SO2 amount. We used these maps to reconstruct time series of SO2 fluxes by integrating profiles of SO2 orthogonal to the plume advection direction and multiplying with wind speeds from a meteorological model. These data were then compared with a reconstructed time series of SO2 fluxes measured with the FLAME ground-based network of ultraviolet DOAS systems surrounding the volcano. We found weak agreement on 3rd December when little ash was emitted, but this agreement improved when a 0.3 m s−1 wind speed correction factor was used. FLAME and MODIS results were in good agreement on the 6th December, and improved when a –0.3 m s−1 offset was applied. The corrected data revealed that the only period of time when FLAME and MODIS did not track together was coincident with the presence of ash, which interferes with the IR imagery and retrieval of SO2. We highlight that combining two independent time series of SO2 flux allows a precise determination of wind speed, if there is sufficient time-dependent structure in the SO2 signal. The observed increase in SO2 flux prior to the ash emission is interpreted as a quiescent release of an accumulated gas phase that drive eruptive activity, as previously suggested for the southeast crater system of Etna. In this case the SO2 flux signal therefore acted as a precursor to the eruptive ash events. This work demonstrates that quantitative reconstruction of SO2 flux time series is feasible using MODIS data, opening a new frontier in the use of satellite data to interpret volcanic processes, in particular in poorly monitored remote locations.

Beschreibung: European Space Agency's Earth Observation Envelope Programme (EOEP) – Data User Element (project SAVAA).

Beschreibung: Published

Beschreibung: 80-87

Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive

Beschreibung: JCR Journal

Beschreibung: reserved

Schlagwort(e): SO2 flux ; Modis ; Etna ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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Time-dependent CO2 variations in Lake Albano associated with seismic activity (2012)

Chiodini, G. ; Tassi, F. ; Caliro, S. ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2024-05-09

Beschreibung: Lake Albano (Alban Hills volcanic complex, Central Italy) is located in a densely populated area near Rome. The deep lake waters have significant dissolved CO2 concentrations, probably related to sub-lacustrine fluid discharges fed by a pressurized CO2-rich reservoir. The analytical results of geochemical surveys carried out in 1989 2010 highlight the episodes of CO2 removal from the lake. The total mass of dissolved CO2 decreased from ∼5.8× 107 kg in 1989 to ∼0.5×107 kg in 2010, following an exponential decreasing trend. Calculated values of both dissolved inorganic carbon and CO2 concentrations along the vertical profile of the lake indicate that this decrease is caused by CO2 release from the epilimnion, at depth 〈9 m, combined with (1) water circulation at depth 〈95 m and (2) CO2 diffusion from the deeper lake layers. According to this model, Lake Albano was affected by a large CO2 input that coincided with the last important seismic swarm at Alban Hills in 1989, suggesting an intimate relationship between the addition of deep-originated CO2 to the lake and seismic activity. In the case of a CO2 degassing event of an order of magnitude larger than the one that occurred in 1989, the deepest part of Lake Albano would become CO2-saturated, resulting in conditions compatible with the occurrence of a gas outburst. These results reinforce the idea that a sudden CO2 input into the lake may cause the release of a dense gas cloud, presently representing the major volcanic threat for this densely populated area

Beschreibung: Published

Beschreibung: 861-871

Beschreibung: 2.4. TTC - Laboratori di geochimica dei fluidi

Beschreibung: 4.5. Studi sul degassamento naturale e sui gas petroliferi

Beschreibung: JCR Journal

Beschreibung: reserved

Schlagwort(e): Crater lakes ; Limnic eruption ; CO2 outburst ; Lake Albano ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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