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  • 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics  (11)
  • 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
  • Mt. Etna
  • Elsevier Science Limited  (17)
  • Springer  (6)
  • Agu
  • Blackwell Publishing Ltd
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • 2010-2014  (24)
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  • 1
    Publikationsdatum: 2021-06-07
    Beschreibung: After the April 6th 2009 MW 6.3 (ML 5.9) L'Aquila earthquake (central Italy), we re-measured more than 100 km of high-precision levelling lines in the epicentral area. The joint inversion of the levelling measurements with InSAR and GPS measurements, allowed us to derive new coseismic and post-seismic slip distributions and to de- scribe, with high resolution details on surface displacements, the activation and the slip distribution of a second- ary fault during the aftershock sequence that struck the Campotosto area (major event MW 5.2). Coseismic slip on the Paganica fault occurred on one main asperity, while the afterslip distribution shows a more complex pattern, occurring on three main patches, including both slips on the shallow portions and on the deeper parts of the rup- ture plane. The comparison between coseismic and post-seismic slip distributions strongly suggests that afterslip was triggered at the edges of the coseismic asperity. The activation of a segment of the Campotosto fault during the aftershock sequence, with a good correlation between the estimated slipping area, moment release and distribution of aftershocks, raises the opportunity to discuss the local seismic hazard following the occurrence of the 2009 L'Aquila mainshock. The Campotosto fault appears capable of generating earthquakes as large as his- torical events in the region (M N 6.5) or as small as the ones associated with the 2009 sequence. In the case that the Campotosto fault is accumulating a significant portion of the current interseismic deformation, the 2009 MW N 5 events will have released only a small amount of the accumulated elastic strain, and then a significant hazard still remains in the area. Continuing geodetic monitoring and a densification of the GPS networks in the region are therefore needed to estimate the tectonic loading across the different recognized active fault systems in this part of the Apennines.
    Beschreibung: Published
    Beschreibung: 168-185
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): High-precision leveling; InSAR; GPS; Earthquake source; Normal faulting; Seismic hazard ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.01. Continents
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2017-04-04
    Beschreibung: The main goal of this study is to provide moment tensor solutions for small and moderate earthquakes of the Matese seismic sequence in southern Italy for the period of December 2013–January 2014. We estimate the focal mechanisms of 31 earthquakes with local magnitudes related to the Matese earthquake seismic sequence (December 2013–January 2014) in Southern-Central Italy which are recorded by the broadband stations of the Italian National Seismic Network and the Mediterranean Very Broadband Seismographic Network (MedNet) run by the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The solutions show that normal faulting is the prevailing style of seismic deformation in agreement with the local faults mapped outin the area. Comparisons with already published solutions and with seismological and geological information available allowed us to properly interpret the moment tensor solutions in the frame of the seismic sequence evolution and also to furnish additional information about less energetic seismic phases. Focal data were inverted to obtain the seismogenic stress in the study area. The results are compatible with the major tectonic domain of the area.
    Beschreibung: Published
    Beschreibung: 118-124
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Moment tensors ; Southern Italy ; Apennines ; Stress inversion ; Seismicity and tectonics ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2021-06-08
    Beschreibung: Source parameters of the mainshock (ML=5.3) and of 165 aftershocks (0.8 〈 ML 〈 3.5) of the 2004 Kobarid (Western Slovenia) seismic sequence are investigated in order to determine the corresponding source scaling relations. Data recorded from July to December 2004 by the Friuli and Veneto seismic network (FV), managed by the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS) and installed in Northeastern Italy, are employed to obtain the SH-wave amplitude Fourier spectra of the selected earthquakes. For source spectra computation, we consider only records with significant values of the signal-to-noise ratio and, to account for local amplifications, we compute standard H/V spectral ratios (HVSR) for all the stations of the network. After correction for attenuation effects, source spectra obtained at stations with negligible site effects show a good fit with a ω-square model. We adopt different approaches to compute the source parameters and final results are chosen based on the obtained misfits between observed and theoretical source spectra. For 21 earthquakes of the sequence the obtained results are confirmed by the Empirical Green Function (EGF) technique, applied by estimating the spectral ratios of couples of events with hypocentral distance differences smaller than 500 m and magnitude differences greater than 1. The mainshock of the sequence is characterized by a seismic moment of 3.5x10^16 Nm and a corner frequency of 0.8 Hz, corresponding, in the Brune’s model (1970), to a fault radius of 1465 m and a stress drop of 4.9 MPa. Aftershocks have seismic moments in the range [3.3x10^11, 1.8x10^14] Nm, corner frequencies between 1.9 and 12.4 Hz (Brune radii between 95 and 638 m) and stress drops in the range [0.03, 1.55] MPa. The observed scaling of seismic moment (M0) with the local magnitude (ML) is consistent with the trend: Log M0 = 1.06 ML + 10.56. The Brune radius (rB) increases with the seismic moment according to: Log rB = 0.22 Log M0 - 0.40. Moreover, in spite of the high dispersion that characterizes the estimates of the Brune stress drop (ΔσB), we observe also an increase of ΔσB with M0. The mainshock is characterized by 2.4 x10^12 J radiated energy (ES) and 1.9 MPa apparent stress (σa). Aftershocks have energies between 2.0 x10^5 and 7.4 x10^8 J and apparent stress values increasing with the seismic moment in the range [0.01, 0.48] MPa. Radiated energies increase with seismic moments according to the empirical relationship: Log ES = 1.53 Log M0 - 12.47. The scaling of both ΔσB and σa with M0 in the range of magnitude between 0.8 to 5.3, evidences the non-self-similarity characteristics of the 2004 Kobarid seismic sequence. Similar results have been obtained by previous studies concerning the source parameter scaling of the background seismicity and of other seismic sequences of the area.
    Beschreibung: Published
    Beschreibung: 58-75
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Earthquakes ; Source parameters ; Scaling law ; Seismic sequences ; Northeastern Italy ; Western Slovenia ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2021-04-07
    Beschreibung: Recognizing the seismogenic source of major historical earthquakes, particularly when these have occurred offshore, is a long-standing issue across the Mediterranean Sea and elsewhere. The destructive earthquake (M ~7) that struck western Calabria (southern Italy) on the night of 8 September 1905 is one such case. having various authors proposed a seismogenic source, with apparently diverse hypotheses and without achieving a unique solution. To gain novel insight into the crustal volume where the 1905 earthquake took place and to seek a more robust solution for the seismogenic source associated with this destructive event, we carried out a well-targeted multidisciplinary survey within the Gulf of S. Eufemia (SE Tyrrhenian Sea), collecting geophysical data, oceanographic measurements, and biological, chemical and sedimentary samples. We identified three main tectonic features affecting the sedimentary basin in the Gulf of S. Eufemia: 1) a NE-SW striking, ca. 13-km-long, normal fault, here named S. Eufemia Fault; 2) a WNW-striking polyphased fault system; and 3) a likely E-W trending lineament. Among these, the normal fault shows evidence of activity witnessed by the deformed recent sediments and by its seabed rupture along which, locally, fluid leakage occurs. Features in agreement with the anomalous distribution of prokaryotic abundance and biopolymeric C content, resulted from the shallow sediments analyses. The numerous seismogenic sources proposed in the literature during the past 15 years make up a composite framework of this sector of western Calabria, that we tested against a) the geological evidence from the newly acquired dataset, and b) the regional seismotectonic models. Such assessment allows us to propose the NE-SW striking normal fault as the most probable candidate for the seismogenic source of the 1905 earthquake. Re-appraising a major historical earthquake as the 1905 one enhances the seismotectonic picture of western Calabria. Further understanding of the region and better constraining the location of the seismogenic source may be attained through integrated interpretation of our data together with a) on-land field evidence, and b) seismological modeling.
    Beschreibung: Published
    Beschreibung: 62-75
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): seismogenic source ; earthquake ; seismotectonics ; prokaryotes ; Calabrian Arc ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    facet.materialart.
    Unbekannt
    Elsevier Science Limited
    Publikationsdatum: 2017-04-03
    Beschreibung: Several fundamental questions (conundrums) about earthquakes and rocks are inexplicable in terms of conventional sub-critical geophysics. These questions have become so familiar that they are now generally accepted as the way earthquakes and rocks behave and are not recognised as presenting conceptual difficulties. These conundrums are resolved by a new understanding of fluid-rock deformation, where fluid-saturated microcracks in almost all rocks are so closely-spaced they verge on failure and hence are highly-compliant critical-systems which impose a range of new properties on conventional sub-critical geophysics. This new understanding of fluid-rock deformation, this New Geophysics, allows earthquakes to be stress-forecast, and has implications and applications to many solid Earth developments.
    Beschreibung: Published
    Beschreibung: 501–509
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Conundrums resolved ; Monitoring stress changes ; Seismic anisotropy ; Shear-wave splitting ; Stress-accumulation ; Stress-relaxation ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2017-04-04
    Beschreibung: On 13 May 2008, an eruption began at Mt. Etna from an eruptive fissure that opened on the upper eastern flank of the volcano. During 12-13 May, 157 infrasonic events, together with the related seismic transients, were collected. We carried out several analyses to obtain dominant frequencies, pseudospectrograms, peak-to-peak amplitudes, source locations and time lags between infrasonic and seismic events. Spectra of the infrasonic events show two main spectral peaks in the frequency bands ~0.4-0.7 Hz and 1.5-2.0 Hz, respectively. Both infrasonic and seismic events were separately located below the North-East Crater, where no eruptive activity was observed. Moreover, significant changes in infrasound spectral content, as well as in the infrasonic-seismic lags, were found a few hours before the beginning of the eruption. On the basis of the collected information the infrasound source mechanism was modelled as a superposition of pipe and Helmholtz resonance, also leading to outline the geometry of the shallower portion of the North-East Crater plumbing system. The occurrence of these seismo-infrasonic events together with other geological and geophysical evidences, led us to inferring a direct link between North-East Crater activity and the eruptive fissure. Further, based on variations over time of both spectral features and seismicinfrasonic time lag, shallowing phenomena of the free magma column inside North-East Crater conduit were hypothesized. Such an uprise of magma was likely caused by a pressure increase inside the plumbing system occurring before the beginning of the 2008-2009 eruption.
    Beschreibung: Published
    Beschreibung: 53-68
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): infrasound ; Helmholtz resonator ; plumbing system geometry ; seismo-acoustic studies ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2017-10-06
    Beschreibung: Themajor elements, trace elements and Sr and Nd isotopes of selected Etnean primitive rocks (b15 ky BP) were studied in order to characterize their mantle source. The noble-gas geochemistry of fluid inclusions in minerals fromthe same lavaswas also investigated. Themajor element compositions ofwhole rocks and minerals showed that these products are among the most primitive atMt. Etna, comprising 6.3–17.5 wt.% MgO. The variable LREE (Light Rare Earth Elements) enrichment relative to MORB (Mid-Ocean Ridge Basalt) (Lan/Ybn = 11–26), togetherwith the patterns of certain trace-element ratios (i.e., Ce/Yb versus Zr/Nb and Th/Y versus La/Yb), can be attributed to varying degrees of melting of a common mantle source. Numerical simulations performed with the MELTS program allowed the melting percentages associated with each product to be estimated. This led us to recalculate the hypothetical parental trace-element content of the Etneanmantle source, whichwas common to all of the investigated rocks. The characteristics of the Sr, Nd and He isotopes confirmed the primitive nature of the rocks,with themost-depleted and primitive lava being that ofMt. Spagnolo (SPA; 143Nd/144Nd = 0.512908 87Sr/ 86Sr = 0.703317–0.703325 and 3He/4He = 7.6 Ra), and highlighted the similarity of the mantle sources feeding the volcanic activity of Mt. Etna and the Hyblean Plateau (a region to the south of Mt. Etna and characterized by oldermagmatismthan Mt. Etna). The coupling of noble gases and trace elements suggests an origin for the investigated Etnean lavas from melting of a Hyblean-like mantle, consisting of a two-component source where a peridotitic matrix is veined by 10% pyroxenite. A variable degree of mantle contamination by crustal-like fluids, probably related to subduction, is proposed to explain the higher Sr-isotope and lowerNd-isotope values in some rocks (143Nd/144Nd up to 0.512865 and 87Sr/86Sr up to 0.703707). This process probably occurred in the source prior tomagma generation, refertilizing some portions of themantle. Accordingly, the estimated degree of melting responsible for each magma appears to be related to its 87Sr/86Sr enrichment. In contrast, the decoupling between 3He/4He and 87Sr/86Sr ratios requires the occurrence in the crustal reservoirs of further processes capable of shifting the He isotope ratio towards slightly more radiogenic values, such as magma aging or a contribution of shallow fluid. Therefore, different residence times in the Etnean reservoir and/or various rates of magma ascent could be key parameters for preserving the original He isotope marker of the Etnean mantle source.
    Beschreibung: Published
    Beschreibung: 243-258
    Beschreibung: 5V. Sorveglianza vulcanica ed emergenze
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Mt. Etna ; Hyblean Plateaux ; Primitive magma ; Mantle metasomatism ; Peridotite ; Pyroxenite ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2021-03-01
    Beschreibung: In this work, we tackle the problem of seismic hazard at Etna deriving from the recurrent seismogenic activity of local faults, by adopting two independent methods based on probabilistic approaches. We assess the hazard in terms of macroseismic intensity and represent the occurrence probability calculated for different exposure times both on maps and at fault scale. Seismic hazard maps obtained by applying the “site approach” through the SASHA code and a new probabilistic attenuation model, indicate the eastern flank of the volcano as the most hazardous, with expected intensity (Iexp) in 50 years (i.e. the standard exposure time adopted in the seismic regulations) ranging from degrees IX to X EMS. In shorter exposure periods (20, 10, 5 years), values of Iexp up to IX are also reached in the same area, but they are clearly determined by the earthquakes generated by the Timpe fault system. In order to quantify the contribution of local seismogenic sources to the hazard of the region, we reconstruct the seismic history of each fault and calculate with SASHA the probability that earthquakes of a given intensity may be generated in different exposure times. Results confirm the high level of hazard due to the S. Tecla, Moscarello and Fiandaca faults especially for earthquakes of moderate intensity, i.e. VI≤I0≤VII, with probabilities respectively exceeding 50% and 20% in 10 years, and 30% and 10% in 5 years. Occurrence probability of major events (I0≥VIII) at the fault scale has also been investigated by statistics on intertimes. Under stationary assumptions we obtain a probability of 6.8% in 5 years for each structure; by introducing the time-dependency (time elapsed since the last event occurred on each fault) through a BPT model, we identify the Moscarello and S. Tecla faults as the most probable sources to be activated in the next 5 years (2013–2017). This result may represent a useful indication to establish priority criteria for actions aimed at reducing seismic risk at a local scale.
    Beschreibung: Published
    Beschreibung: 158-169
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Macroseismic intensity ; Seismic history ; Occurrence probability ; Time-dependent renewal process ; Individual sources ; Seismic hazard ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2021-03-01
    Beschreibung: In this paper, we apply a probabilistic procedure to model the attenuation of the macroseismic intensity in the Mt. Etna region, which allows estimating probabilistic seismic scenarios. Starting from the local earthquake catalogue, we select a dataset of 47 events having epicentral intensity I0 from VI to IX–X EMS, and update the model parameters previously achieved for Italy according to the Bayesian paradigm. For each class of epicentral intensity I0, we then estimate the probability distribution of the intensity at a site conditioned on the epicentre-site distance through a binomial-beta model, under the assumption of a point seismic source and isotropic decay (circular). The mode of the distribution is taken as the expected intensity Is at that site. Since the strongest earthquakes show a preferential propagation of shaking along the fault strike and a rapid decrease in the perpendicular direction, we also consider the anisotropic decay (elliptical) of the intensity due to a linear source (finite fault). We therefore transform the plane so that the ellipse has the length of the fault rupture as maximum axis and its strike as azimuth is changed into a circle with fixed diameter; then we apply the probabilistic model obtained for the isotropic case to the modified data. The entire calculation procedure is implemented in the software PROSCEN which, given the location and the epicentral intensity (and eventually the fault parameters) of the earthquake to be simulated, generates the probabilistic seismic scenario according to the isotropic and anisotropic models of attenuation. The results can be plotted on grid maps representing (1) the intensity that can be exceeded with a fixed probability, or (2) the probability of exceeding a fixed intensity value. The first representation may also find application in seismic monitoring at Etna volcano, in order to produce real-time intensity ShakeMaps based on the instrumental parameters calculated by the automatic earthquake processing system.
    Beschreibung: Published
    Beschreibung: 149-157
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Macroseismic intensity ; Attenuation Probability distribution ; Source models ; Seismic scenario ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 10
    facet.materialart.
    Unbekannt
    Elsevier Science Limited
    Publikationsdatum: 2017-04-03
    Beschreibung: Fluorine adsorption experiments were performed on 28 samples of the first 5 cm of topsoil collected on the flanks of Mt. Etna. The soil samples were equilibrated with F-rich rainwater (3.25 mg/L) at a soil/water weight ratio of 1/25. Aliquots of the supernatant were collected after 1, 7, 72, 720 and 5640 h and analysed for F content. The soil samples could be subdivided into three groups based on their F-adsorption behaviours after 1 h and at the end of the experiment: (1) negative adsorption (F released from the soil to the solution) after 1 h and negative or moderately positive adsorption at the end, (2) from negative after 1 h to strongly positive adsorption at the end, and (3) always strong positive adsorption. The adsorption capacity of the soils was positively correlated with the soil pH, the contents of finer granulometric fractions (clay and silt) and the weathering stage (as quantified by the chemical alteration index). The most F adsorbing soils are found at the periphery of the volcano where aquifers are more vulnerable to contamination due to the shallower depth of the water table. This study further evidences the importance of the Etnean soils in protecting groundwater from an excessive magmatic F input.
    Beschreibung: Published
    Beschreibung: 1179–1188
    Beschreibung: 4.4. Scenari e mitigazione del rischio ambientale
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): volcanic soils ; fluoride adsorption ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.08. Risk::05.08.01. Environmental risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 11
    Publikationsdatum: 2017-04-04
    Beschreibung: Understanding the behavior of natural faults at cosesimic slip velocities (v ~ 1–10 m/s or more) has become a challenging achievement for experimentalists and modelers of earthquake instabilities. The rate– and state–dependent friction laws, originally obtained in slow slip rate conditions, have been widely adopted in dynamic rupture models by assuming their validity well above the experimental range of observations. In this paper we consider a modification at high speeds, in which the steady state friction becomes independent on v above a transitional value vT . Our results show that this modification has dramatic effects on the dynamic propagation; as long as vT decreases the breakdown stress drop decreases, as well as the slip–weakening distance and the fracture energy density. Moreover, we found that the subshear regime is favored as vT decreases; we found that for the strength parameter S greater than 1.482 the supershear rupture propagation is inhibited. Finally, we demonstrate that the exponential weakening, often observed in laboratory experiments, can be theoretically explained in the framework of the rate and state laws.
    Beschreibung: Published
    Beschreibung: 223-230
    Beschreibung: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Rheology of faults ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 12
    Publikationsdatum: 2017-04-04
    Beschreibung: To recognize possible spatial clusters and identify active seismogenic zones and structures in the Aeolian Archipelago, in the south of Italy, we analyzed the spatial pattern of seismicity between 1993 and 2010 in a selected area comprising Vulcano, Lipari, Salina and Filicudi and calculated 22 fault plane solutions (FPSs) for shocks with magnitude greater than 2.7. First, we computed a 1-D velocity model for this area including information from recorded earthquakes by a joint hypocenter-velocity inversion (Kissling et al., 1994). Successively, we applied the double-difference approach of Waldhauser and Ellsworth (2000), finding that a certain part of the scattered epicenter locations collapse in roughly linear features. Relocated seismicity evidenced three main alignments, oriented NNW-SSE and NE-SW at different depths that concur well with the known tectonic lineaments and focal mechanisms. A detailed discussion is focused on a seismogenetic structure, NE-SW oriented, 3-8 km deep, located in the northern area of Vulcano island. This recognized element could represent a link between magma accumulation zones, thus representing a possible preferential pathway along which magma may intrude. Two earthquake clusters, located south-west and east of Vulcano, with their focal mechanisms, highlight the Aeolian-Tindari-Letojanni Fault System seismic activity and the existence of a transitional zone going from the N-S compressive domain that dominates the Aeolian Islands to the NW-SE extensional domain characterizing the south-eastern Thyrrhenian.
    Beschreibung: Published
    Beschreibung: 108-115
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Earthquake relocation ; Fault plane geometry ; Aeolian islands ; Magma dynamics ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Publikationsdatum: 2017-04-04
    Beschreibung: In this work we propose a high performance parallelization of the software package COMPSYN, devoted to the production of syntethic seismograms, on a cluster of multicore processors with multiple GPUs. To design and implement the proposed high performance version, we started from a na¨ıve parallel version of COMPSYN. The na¨ıve version consists in a simple parallelization on both device side, obtained by exploiting CUDA, and host side, obtained by exploiting the MPI paradigm and OpenMP API. The proposed high performance version implements several practical techniques of CUDA programming and deeply exploits the GPU architecture, thus achieving a much better performance with respect to the na¨ıve version. We compare the performance of the proposed high performance version and that of the na¨ıve one with the performance of the version running on the cluster of multicore processors without invoking the GPUs. We obtain for the high performance GPU version a speedup of 25x over the version running on the cluster of multicore processors without GPUs against the 10x of the na¨ıve version. Regarding the sequential version, we estimate about 380x the speedup of the high performance GPU version against the about 140x of the na¨ıve version.
    Beschreibung: Collaboration Agreement between Dept. of Computer Science, Sapienza University of Rome and Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy, 2011. Project n. C26G074ABJ, 2007, Cluster of multicore processor for advanced computation, Sapienza University of Rome.
    Beschreibung: Published
    Beschreibung: 966-975
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: N/A or not JCR
    Beschreibung: restricted
    Schlagwort(e): GPU ; CUDA ; synthetic seismogram ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Publikationsdatum: 2017-04-04
    Beschreibung: Since January 2008, several geophysical parameters have evidenced a recharging phase at Mt. Etna volcano culminating with an effusive eruption that began on May 13, 2008. Seismic activity recorded at Mt. Etna from January 2007 to May 2008 was analyzed in order to provide seismological constraints to the volcano dynamics leading to the eruption. A total of 336 selected earthquakes, withML≥1.5, were used as data source for this study. Specifically, we calculated 3D velocity and attenuation tomography, including a 3D relocation of the events, and we computed 53 selected fault plane solutions (FPSs) that were used for stress tensor inversion. The most important result obtained from the joint analysis of VP, VP/VS and P-wave attenuation is an anomalous zone with normal to high VP (values between 3.5 and 4.5 km/s) and low VP/VS (values≤1.64), which partially overlaps with a low QP (values≤50) volume located along a NS trending channel beneath the central crater. This can be interpreted as a shallow volume characterized by high temperature where the magma is located with the presence of supercritical fluids. The analysis of seismic stress tensor evidenced an extensional regime in the depth range 3–13 km with a vertically oriented σ1. This finding may suggest an extensional stress regime, probably related to the kinematic response of the volcanic edifice to both a deep magmatic intrusion and a condition of decreased regional compressive stress facilitated by sliding processes of the eastern flank of the volcano.
    Beschreibung: Published
    Beschreibung: 50–63
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Mt. Etna ; Volcanic eruptions ; Stress Tensor ; Velocity tomography ; Attenuation tomography ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Publikationsdatum: 2017-04-04
    Beschreibung: Using a lava flow emplacement model and a satellite-based land cover classification, we produce a map to allow assessment of the type and quantity of natural, agricultural and urban land cover at risk from lava flow invasion. The first step is to produce lava effusion rate contours, i.e., lines linking distances down a volcano’s flank that a lava flow will likely extend if fed at a given effusion rate from a predetermined vent zone. This involves first identifying a vent mask and then running a downhill flow path model from the edge of every pixel around the vent mask perimeter to the edge of the DEM. To do this, we run a stochastic model whereby the flow path is projected 1,000 times from every pixel around the vent mask perimeter with random noise being added to the DEM with each run so that a slightly different flow path is generated with each run. The FLOWGO lava flow model is then run down each path, at a series of effusion rates, to determine likely run-out distance for channel-fed flow extending down each path. These results are used to plot effusion rate contours. Finally, effusion rate contours are projected onto a land classification map (produced from an ASTER image of Etna) to assess the type and amount of each land cover class falling within each contour. The resulting maps are designed to provide a quick look-up capability to assess the type of land at risk from lava extending from any location at a range of likely effusion rates. For our first (2,000 m) vent zone case used for Etna, we find a total of area of ~680 km2 is at risk from flows fed at 40 m3 s−1, of which ~6 km2 is urban, ~150 km2 is agriculture and ~270 km2 is grass/woodland. The model can also be run for specific cases, where we find that Etna’s 1669 vent location, if active today, would likely inundate almost 11 km2 of urban land, as well as 15.6 km2 of agricultural land, including 9.5 km2 of olive groves and 5.2 km2 of vineyards and fruit/nut orchards.
    Beschreibung: Published
    Beschreibung: 1001-1027
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Lava flow ; Risk ; FLOWGO ; ASTER image ; Land classification ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    facet.materialart.
    Unbekannt
    Elsevier Science Limited
    Publikationsdatum: 2017-04-03
    Beschreibung: In this paper we consider a wide catalog of synthetic earthquakes, numerically modeled as spontaneous, fully dynamic, 3-D ruptures on extended faults, governed by different friction laws, including slip-dependent and rate- and state-dependent equations.We analyze the spatial correlations between the peak of fault slip velocity (v_peak) and the rupture speed (v_r) at which the earthquake spreads over the fault. We found that vpeak positively correlates with vr and that the increase of v_peak is roughly quadratic. We found that near the transition between sub- and supershear regimes vpeak significantly diminishes and then starts to increase againwith the square of v_r. This holds for all the governing models we consider and for both homogeneous and heterogeneous configurations. Moreover, we found that, on average, v_peak increases with the magnitude of the event (v_peak~M_0^0.18). Our results can be incorporated as constraints in the inverse modeling of faults.
    Beschreibung: Published
    Beschreibung: 196-204
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Dynamic models ; Fault mechanics ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Publikationsdatum: 2017-04-04
    Beschreibung: Earthquakes are the result of a combination of (1) physico-chemical processes operating in fault zones. which allow ruptures to nucleate and rock friction to decrease with increasing slip or slip rate, and (2) of the geometrical complexity of fault zones. In this review paper, we summarize recent experimental findings from high velocity (conducted at about 1 m/s slip rate, or typical seismic slip rates) rock friction experiments with an emphasis on potential dynamic weakening mechanisms (melt lubrication, nano-powder lubrication, etc.) and how these mechanisms might be recognized by means of microstructural and mineralogical studies in exhumed fault zones. We discuss how earthquake source parameters (coseismic fault strength, weakening distances, energy budgets, etc.) might be derived from the field and laboratory experiments. Additionally, we discuss what needs to be considered in terms of fault zone geometry and morphology (focusing on fault surface roughness) in order to develop models of realistic fault surfaces and present theoretical considerations for microphysical modeling of laboratory data at seismic slip rates, with an emphasis on the case of melt lubrication. All experimental data and, in the case of melt lubrication, microphysical models indicate that faults must be very weak (mu 〈 0.1) during coseismic slip. Moreover, experiments have shown that the slip weakening distance during coseismic slip is on the order of a few tens of centimeters at most under natural conditions, consistent with inferences from field observations. Finally, we discuss open questions, future challenges and opportunities in the field of earthquake mechanics. (C) 2012 Elsevier Ltd. All rights reserved.
    Beschreibung: Published
    Beschreibung: 2-36
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): earthquake physics ; friction ; high velocity friction experiments ; experimental ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    facet.materialart.
    Unbekannt
    Elsevier Science Limited
    Publikationsdatum: 2017-04-04
    Beschreibung: Though mode II shear fractures (primarily strike–slip earthquakes) can not only exceed the shear wave speed of the medium, but can even reach the compressional wave speed, steady–state calculations showed that speeds between the Rayleigh and shear wave speeds were not possible, thus defining a forbidden zone. For more than 30 years it was believed that this result in which the rupture jumps over the forbidden zone, also holds for 3–D ruptures, in which mode II and mode III (mainly dip–slip faulting) are mixed. Using unprecedentedly fine spatial and temporal grids, we show that even in the simple configuration of homogeneous fault properties and linear slip–weakening friction law, a realistic 3–D rupture which starts from rest and accelerates to some higher velocity, actually does pass smoothly through this forbidden zone, but very fast. The energy flux from the rupture tip is always positive, even within the so-called forbidden zone, contrary to the 2–D case. Finally, our results show that the width of the cohesive zone initially decreases, then increases as the rupture exceeds the shear wave speed and finally again decreases as the rupture accelerates to a speed of ~ 90% of the compressional wave speed.
    Beschreibung: Published
    Beschreibung: 397-404
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Supershear earthquakes ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    Publikationsdatum: 2023-06-05
    Beschreibung: A detailed analysis of the earthquake effects on the urban area of Rome has been conducted for the L’Aquila sequence, which occurred in April 2009, by using an on-line macroseismic questionnaire. Intensity residuals calculated using the mainshock and four aftershocks are analyzed in the light of a very accurate and original geological reconstruction of the subsoil of Rome based on a large amount of wells. The aim of this work is to highlight ground motion amplification areas and to find a correlation with the geological settings at a sub-regional scale, putting in evidence the extreme complexity of the phenomenon and the difficulty of making a simplified model. Correlations between amplification areas and both near-surface and deep geology were found. Moreover, the detailed scale of investigation has permitted us to find a correlation between seismic amplification in recent alluvial settings and subsiding zones, and between heard seismic sound and Tiber alluvial sediments.
    Beschreibung: Published
    Beschreibung: 425-443
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Earthquakes ; Intensity residuals ; Urban geosciences ; Macroseismic effects ; Amplification areas ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Publikationsdatum: 2020-11-18
    Beschreibung: By analyzing surface latent heat flux (SLHF) data from the NCEP/NCAR Reanalysis Project for the period three months before and after the Sept. 3, 2010 MS 7.1 New Zealand earthquake, an isolated SLHF positive anomaly on Aug. 1, 2010 was found with a high value of about 160 W/m2 to the northeast of the epicenter. Historical data, background pixels, and wavelet transforms of time series were comprehensively analyzed to study the spatiotemporal features of the SLHF anomaly. After removing the influences of wind speed and cloud cover, the key factor leading to local SLHF anomalies is the surface temperature increment. Combined with GPS displacement observations and tectonic settings, we determined that the physical mechanism of the SLHF anomaly could possibly be attributed to hot underground materials related to high-temperature and high-pressure upwelling from the deep crust and mantle along the nearby subduction zone, thereby explaining the local temperature increment to the northeast of the epicenter, as well as in the center of the North Island and the southwest of the South Island. Furthermore, it changed the specific humidity between the ground and surface air, causing the local SLHF increment.
    Beschreibung: Published
    Beschreibung: 3273-3280
    Beschreibung: 1.7. Osservazioni di alta e media atmosfera
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): remote sensing ; earthquakes ; precursors ; 01. Atmosphere::01.01. Atmosphere::01.01.05. Radiation ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Publikationsdatum: 2020-11-16
    Beschreibung: Active volcanoes characterized by open conduit conditions generate sonic and infrasonic signals, whose investigation provides useful information for both monitoring purposes and studying the dynamics of explosive processes. In this work, we discuss the automatic procedures implemented for a real-time application to the data acquired by a permanent network of five infrasound stations running at Mt. Etna volcano. The infrasound signals at Mt. Etna consist in amplitude transients, called infrasound events. The adopted procedure uses a multi-algorithm approach for event detection, counting, characterization and location. It is designed for an efficient and accurate processing of infrasound records provided by single-site and array stations. Moreover, the source mechanism of these events can be investigated off-line or in near real-time by using three different models: i) Strombolian bubble; ii) resonating conduit and iii) Helmholtz resonator. The infrasound waveforms allow us to choose the most suitable model, to get quantitative information about the source and to follow the time evolution of the source parameters.
    Beschreibung: Published
    Beschreibung: 1215–1231
    Beschreibung: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): infrasound ; monitoring system ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    Publikationsdatum: 2017-04-04
    Beschreibung: The Irpinia Seismic Network (ISNet) is deployed in Southern Apennines along the active fault system responsible for the 1980, November 23, MS 6.9 Campania-Lucania earthquake. It is comprised of 28 stations and covers an area of about 100x70 km2. Each site is equipped with a 1-g full-scale accelerometer and a short-period velocimeter. Thanks to its design characteristics, i.e. the wide dynamic recording range and the high density of stations, the ISNet network is mainly devoted to estimating in real-time the earthquake location and magnitude from low- to high- magnitude events, and to providing ground-motion parameters to get some insights about the ground shaking expected. Moreover, the availability of high-quality data allows studying the source processes related to the seismogenetic structures in the area. The network layout, the data communication system and protocols and the main instrumental features are described in the paper. Most of the data analysis is performed through the Earthworm software package, that also provides the automatic earthquake locations, while custom software has been developed for real-time computation of the source parameters and shaking maps. Technical details about these procedures are given in the article. The data collected at the ISNet stations are available upon request.
    Beschreibung: Published
    Beschreibung: 1105-1129
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): early warning ; real time seismology ; Irpinia region ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Publikationsdatum: 2017-04-04
    Beschreibung: We image the rupture history of the 2009 L’Aquila (Central Italy) earthquake using a nonlinear joint inversion of strong motion and GPS data. This earthquake ruptured a normal fault striking along the Apennines axis and dipping to the SW. The inferred slip distribution is heterogeneous and characterized by a small, shallow slip patch located up-dip from the hypocenter (9.5 km depth) and a large, deeper patch located southeastward. The rupture velocity is larger in the up-dip than in the along-strike direction. This difference can be partially accounted by the crustal structure, which is characterized by a high velocity layer above the hypocenter and a lower velocity below. The latter velocity seems to have affected the along strike propagation since the largest slip patch is located at depths between 9 and 14 km. The imaged slip distribution correlates well with the on-fault aftershock pattern as well as with mapped surface breakages.
    Beschreibung: Published
    Beschreibung: L19304
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 2009 L'Aquila earthquake ; kinematic inversion ; joint inversion ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Publikationsdatum: 2022-05-24
    Beschreibung: National seismic risk maps are an important risk mitigation tool as they can be used for the prioritization of regions within a country where retrofitting of the building stock or other risk mitigation measures should take place. The production of a seismic risk map involves the convolution of seismic hazard data, vulnerability predictions for the building stock and exposure data. The seismic risk maps produced in Italy over the past 10 years are compared in this paper with recent proposals for seismic risk maps based on state-of-the-art seismic hazard data and mechanics-based vulnerability assessment procedures. The aim of the paper is to open the discussion for the way in which future seismic risk maps could be produced, making use of the most up-to-date information in the fields of seismic hazard evaluation and vulnerability assessment.
    Beschreibung: Published
    Beschreibung: 149–180
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Seismic risk ; Seismic hazard ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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