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We present SEISC-3D, an ArcGIS geodatabase for 3D SEIsmic Source Characterization. It integrates multi-scale and multi-depth geological and seismological information in a compressional environment to build a detailed regional-scale,... more
We present SEISC-3D, an ArcGIS geodatabase for 3D SEIsmic Source Characterization. It integrates multi-scale and multi-depth geological and seismological information in a compressional environment to build a detailed regional-scale, geometric and kinematic, 3D curvilinear fault model suitable for seismic hazard modelers and seismotectonic purposes and geodynamic modeling. This first release focuses on the late Pliocene-to-Quaternary arcuate and eastward convex fold-and-thrust belt still active along the Outer front of the Italian Apennines in eastern Central Italy. The near-surfaces, onshore, and offshore thrust faults represent the hanging-wall structures of a potentially seismogenic regional shear zone, known as Adriatic Basal Thrust, which develops from near-surface to MOHO depths (about 35 km).Three hierarchic levels of structural maps are provided with decreasing details moving from fold-and-thrusts traces, enveloping thrust, and regional thrust alignments.Different datasets (p...
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In any probabilistic seismic hazard analysis (PSHA), the computation of earthquake forecasting models is a fundamental step. A widely used approach is the smoothed seismicity, which uses seismic catalogs to produce earthquake forecasts in... more
In any probabilistic seismic hazard analysis (PSHA), the computation of earthquake forecasting models is a fundamental step. A widely used approach is the smoothed seismicity, which uses seismic catalogs to produce earthquake forecasts in time, space, and magnitude. Early smoothed seismicity models, called fixed smoothing, used spatially uniform smoothing parameters such that the kernels were invariant to spatial variations in seismicity rate. However, recently developed adaptive smoothing methods spatially adapt the smoothing parameters according to the earthquake density. All these fixed or adaptive methods are mainly used in regions with complex seismic source characterization since they do not rely on geological, tectonic, or geodetic information, and they overcome the difficulties in characterizing and segmenting complex geological set-ups. Nevertheless, the standard smoothed seismicity approaches may not properly present the seismicity rates for complex seismotectonic areas.In...
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The Amatrice (Mw 6.0) - Visso (Mw 5.9) - Norcia (Mw 6.5) seismic sequence (hereafter AVN) struck the Central Apennines (Italy) in 6-7 months during 2016-2017, and it has been widely associated with fluid migration in the normal faults... more
The Amatrice (Mw 6.0) - Visso (Mw 5.9) - Norcia (Mw 6.5) seismic sequence (hereafter AVN) struck the Central Apennines (Italy) in 6-7 months during 2016-2017, and it has been widely associated with fluid migration in the normal faults network. The analysis of attenuation parameters (e.g., scattering and absorption) gives information about material properties and the presence of fluids and fracturing. In this study, we investigate in a 3D mapping the scattering contribution to the total attenuation of the AVN seismic sequence (August 2016-January 2017), together with a pre-sequence dataset (March 2013-August 2016). We applied peak delay as a proxy of seismic scattering, to obtain further information on the fracturing processes in time and space. Previous 2D mapping of peak-delay time and coda attenuation tomography in the same study area indicated a substantial control on the scattering of seismic waves by structural (e.g., Monti Sibillini thrust) and lithological (e.g., Umbria- Marc...
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The Amatrice–Visso–Norcia seismic sequence struck Central Italy across the Apenninic normal fault system in 2016. Fluids likely triggered the sequence and reduced the stability of the fault network following the first earthquake... more
The Amatrice–Visso–Norcia seismic sequence struck Central Italy across the Apenninic normal fault system in 2016. Fluids likely triggered the sequence and reduced the stability of the fault network following the first earthquake (Amatrice, Mw 6.0), with their migration nucleating the Visso (Mw 5.9) and Norcia (Mw 6.5) mainshocks. However, both spatial extent and mechanisms of fluid migration and diffusion through the network remain unclear. High fluid content, enhanced permeability, and pervasive microcracking increase seismic attenuation, but different processes contribute to different attenuation mechanisms. Here, we measured and mapped peak delay time and coda attenuation, using them as proxies of seismic scattering and absorption before and during the sequence. We observed that the structural discontinuities and lithology control the scattering losses at all frequencies, with the highest scattering delineating carbonate formations within the Gran Sasso massif. The Monti Sibillin...
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Research Interests: Geology and Seismology
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We forecast time‐independent and time‐dependent earthquake ruptures in the Marmara region of Turkey for the next 30 years using a new fault segmentation model. We also augment time‐dependent Brownian passage time (BPT) probability with... more
We forecast time‐independent and time‐dependent earthquake ruptures in the Marmara region of Turkey for the next 30 years using a new fault segmentation model. We also augment time‐dependent Brownian passage time (BPT) probability with static Coulomb stress changes (ΔCFF) from interacting faults. We calculate Mw > 6.5 probability from 26 individual fault sources in the Marmara region. We also consider a multisegment rupture model that allows higher‐magnitude ruptures over some segments of the northern branch of the North Anatolian Fault Zone beneath the Marmara Sea. A total of 10 different Mw = 7.0 to Mw = 8.0 multisegment ruptures are combined with the other regional faults at rates that balance the overall moment accumulation. We use Gaussian random distributions to treat parameter uncertainties (e.g., aperiodicity, maximum expected magnitude, slip rate, and consequently mean recurrence time) of the statistical distributions associated with each fault source. We then estimate u...
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Research Interests: Geology, Geochemistry, Geophysics, Seismology, Lithology, and 3 moreBorehole, Seismic Noise, and Bay
We perform a regional study in order to provide the seismic hazard community of Israel with new predictive relationships for the earthquake-induced ground motion in Israel. This work is essential for the development of a new generation of... more
We perform a regional study in order to provide the seismic hazard community of Israel with new predictive relationships for the earthquake-induced ground motion in Israel. This work is essential for the development of a new generation of hazard maps, for the planning of the development of the Israel’s region, and the design of earthquake resistant structures and facilities. The main goals of our work is to provide a quantitative description of the expected ground motion within the Israel region, as a function of the hypocentral distance and frequency of motion. For this purpose we use the regression technique that was proposed by Yazd (1993), Herrmann (1999), Raoof et al., (1999) and Malagnini et al.,(2002). The undoubted advantage of this method is the possibility to use for analysis the data of frequent, small earthquakes that are typical for this region. In our analyses we use 4786 waveforms recorded by 30 stations of the Israel Seismic Network from 2000 to 2005. We restricted o...
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In this study we report seismological evidence for the onset and emplacement of the final intrusion which fed the July 18- August 10, 2001 lateral eruption at Mt. Etna volcano. The shallow intrusion and the opening of the fracture system... more
In this study we report seismological evidence for the onset and emplacement of the final intrusion which fed the July 18- August 10, 2001 lateral eruption at Mt. Etna volcano. The shallow intrusion and the opening of the fracture system on July 13-18 were accompanied by one of the most relevant swarms recorded in the last 20 years. The overall
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By means of equation (3), we have computed the probability of occurrence for a characteristic earthquake on each fault segments under the Poisson and BPT distributions, for the next 50 yrs. starting on January, 1 2014. The computation... more
By means of equation (3), we have computed the probability of occurrence for a characteristic earthquake on each fault segments under the Poisson and BPT distributions, for the next 50 yrs. starting on January, 1 2014. The computation starts at the time of occurrence of the first characteristic earthquake on each segment and the elapsed time is reset to zero upon the occurrence of every subsequent event. The computations are repeated 100 times in a Monte Carlo procedure by randomly drawing both the inter-event time and the coefficient of variation from a normal (or Gaussian) distribution within their respective uncertainties. Among the 100 outcomes, we have considered the 16th, 50th and 84th percentiles.
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In recent years, new approaches for developing earthquake rupture forecasts (ERFs) have been proposed to be used as an input for probabilistic seismic hazard assessment (PSHA). Zone- based approaches with seismicity rates derived from... more
In recent years, new approaches for developing earthquake rupture forecasts (ERFs) have been proposed to be used as an input for probabilistic seismic hazard assessment (PSHA). Zone- based approaches with seismicity rates derived from earthquake catalogs are commonly used in many countries as the standard for national seismic hazard models. In Italy, a single zone- based ERF is currently the basis for the official seismic hazard model. In this contribution, we present eleven new ERFs, including five zone-based, two smoothed seismicity-based, two fault- based, and two geodetic-based, used for a new PSH model in Italy. The ERFs were tested against observed seismicity and were subject to an elicitation procedure by a panel of PSHA experts to verify the scientific robustness and consistency of the forecasts with respect to the observations. Tests and elicitation were finalized to weight the ERFs. The results show a good response to the new inputs to observed seismicity in the last few c...
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In this paper we report seismological evidence regarding the emplacement of the dike that fed the July 18 - August 9, 2001 lateral eruption at Mt. Etna volcano. The shallow intrusion and the opening of the eruptive fracture system, which... more
In this paper we report seismological evidence regarding the emplacement of the dike that fed the July 18 - August 9, 2001 lateral eruption at Mt. Etna volcano. The shallow intrusion and the opening of the eruptive fracture system, which mostly occurred during July 12, and July 18, were accompanied by one of the most intense seismic swarms of the last 20 years. A total of 2694 earthquakes (1 £ Md £ 3.9) were recorded from the beginning of the swarm (July 12) to the end of the eruption (August 9). Seismicity shows the upward migration of the dike from the basement to the relatively thin volcanic pile. A clear hypocentral migration was observed, well constraining the upwards propagation of a near-vertical dike, oriented roughly N-S, and located a few kilometers south of the summit region. Earthquake distribution and orientation of the P-axes from focal mechanisms indicate that the swarm was caused by the local stress source related to the dike intrusion.
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In this study we investigate directivity effects associated to the Mw6.0 Amatrice earthquake taking into account the source rupture heterogeneities. We use the directivity predictor proposed by Spudich et al. (2004) which is derived from... more
In this study we investigate directivity effects associated to the Mw6.0 Amatrice earthquake taking into account the source rupture heterogeneities. We use the directivity predictor proposed by Spudich et al. (2004) which is derived from the isochrones theory. The directivity is computed using a source to site geometry and a focal mechanism. For its simplicity it can be computed once that a moment tensor solution is available. We use this technique to validate the real time solutions. Moreover, because the directivity predictor depends on the rupture velocity it can be used as a proxy to validate the possible rupture history. For the aforementioned reasons our method revealed fruitful for real time applications and helpful to constrain a few main rupture features for further analysis.
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The 2016 August 24 Amatrice earthquake occurred at 03:36 local time in Central Apennines Italy with an epicentre at 43.36°E, 38.76°N, Istituto Nazionale di Geofisica e Vulcanologia (INGV), few kilometers north of the city of Amatrice. The... more
The 2016 August 24 Amatrice earthquake occurred at 03:36 local time in Central Apennines Italy with an epicentre at 43.36°E, 38.76°N, Istituto Nazionale di Geofisica e Vulcanologia (INGV), few kilometers north of the city of Amatrice. The earthquake ruptured a North-West (NW)–South-East (SE) oriented normal fault dipping toward the South-West (SW) (Scognamiglio et al., 2016). High values of peak ground acceleration (~0.45 g) were observed close to Amatrice (3 stations being few kilometer distances from the fault). The present study presents an overview of the main features of the seismic ground shaking during the Amatrice earthquake. We analyze the ground motion characteristics of the main shock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations (SA, 5 per cent of critical damping). In order to understand the characteristics of the ground motions induced by Amatrice earthquake, we also study the source-related effects relative to the fa...
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The recent Amatrice strong event (Mw6.0) occurred on August 24, 2016 in Central Apennines (Italy) in a seismic gap zone, motivated us to study and provide better understanding of the seismic hazard assessment in the macro area defined as... more
The recent Amatrice strong event (Mw6.0) occurred on August 24, 2016 in Central Apennines (Italy) in a seismic gap zone, motivated us to study and provide better understanding of the seismic hazard assessment in the macro area defined as “Central Italy”. The area affected by the sequence is placed between the Mw6.0 1997 Colfiorito sequence to the north (Umbria-Marche region) the Campotosto area hit by the 2009 L’Aquila sequence Mw6.3 (Abruzzo region) to the south. The Amatrice earthquake occurred while there was an ongoing effort to update the 2004 seismic hazard map (MPS04) for the Italian territory, requested in 2015 by the Italian Civil Protection Agency to the Center for Seismic Hazard (CPS) of the Istituto Nazionale di Geofisica e Vulcanologia INGV. Therefore, in this study we brought to our attention new earthquake source data and recently developed ground-motion prediction equations (GMPEs). Our aim was to validate whether the seismic hazard assessment in this area has change...
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On 30 October 2020 a MW 7.0 earthquake occurred in the eastern Aegean Sea, between the Greek island of Samos and Turkey’s Aegean coast, causing considerable seismic damage and deaths, especially in the Turkish city of Izmir, approximately... more
On 30 October 2020 a MW 7.0 earthquake occurred in the eastern Aegean Sea, between the Greek island of Samos and Turkey’s Aegean coast, causing considerable seismic damage and deaths, especially in the Turkish city of Izmir, approximately 70 km from the epicenter. In this study, we provide a detailed description of the Samos earthquake, starting from the fault rupture to the ground motion characteristics. We first use Interferometric Synthetic Aperture Radar and Global Positioning System data to constrain the source mechanisms. Then, we utilize this information to analyze the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity, and spectral pseudo-accelerations. Modelling of geodetic data shows that the Samos earthquake ruptured a NNE-dipping normal fault located offshore north of Samos, with up to 2.5–3 m of slip and an estimated geodetic moment of 3.3 ⨯ 1019 Nm (MW 7.0). Although low PGA were induced by the earthquake, the ground shaking was strongly amplified in Izmir throughout the alluvial sediments. Structural damage observed in Izmir reveals the potential of seismic risk due to the local site effects. To better understand the earthquake characteristics, we generated and compared stochastic strong ground motions with the observed ground motion parameters as well as the ground motion prediction equations, exploring also the efficacy of the region-specific parameters which may be used to better predict the expected ground shaking from future large earthquakes in the region.
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SUMMARYOn 24 January 2020 an Mw 6.8 earthquake occurred at 20:55 local time (17:55 UTC) in eastern Turkey, close to the town of Sivrice in the Elazığ province, causing widespread considerable seismic damage in buildings. In this study, we... more
SUMMARYOn 24 January 2020 an Mw 6.8 earthquake occurred at 20:55 local time (17:55 UTC) in eastern Turkey, close to the town of Sivrice in the Elazığ province, causing widespread considerable seismic damage in buildings. In this study, we analyse the main features of the rupture process and the seismic ground shaking during the Elazığ earthquake. We first use Interferometric Synthetic Aperture Radar (InSAR) interferograms (Sentinel-1 satellites) to constrain the fault geometry and the coseismic slip distribution of the causative fault segment. Then, we utilize this information to analyse the ground motion characteristics of the main shock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations. The absence of seismic registrations in near-field for this earthquake imposes major constraints on the computation of seismic ground motion estimations in the study area. To do this, we have used a stochastic finite-fault simulation method to generat...
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... 1). Teleseismic receiver functions (Langston, 1979) provide valuable information on the largest S-wave velocity contrast within the structure local to the recording station (Ammon et al., 1990). ... Dr. Charles Langston is also... more
... 1). Teleseismic receiver functions (Langston, 1979) provide valuable information on the largest S-wave velocity contrast within the structure local to the recording station (Ammon et al., 1990). ... Dr. Charles Langston is also thanked for critically reviewing the manuscript. ...
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This research focuses on predicting and assessing earthquake impact due to future scenarios regarding the ground motion seismic hazard by accounting mainly for site effect in the Central Apennines. To this end, we produced synthetic... more
This research focuses on predicting and assessing earthquake impact due to future scenarios regarding the ground motion seismic hazard by accounting mainly for site effect in the Central Apennines. To this end, we produced synthetic broadband seismograms by adopting a hybrid simulation technique for the Mw6.0 Amatrice earthquake, Central Italy, on 24 August 2016, accounting for site conditions by means of amplification curves, computed with different approaches. Simulations were validated by comparing with data recorded at 57 strong-motion stations, the majority installed in urban areas. This station sample was selected among stations recording the Amatrice earthquake within an epicentral distance of 150 km and potentially prone to experience site amplification effects because of lying in particular site conditions (sedimentary basins, topographic irregularities, and fault zones). The evaluation of amplification curves best suited to describe local effects is of great importance bec...
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<p>The Amatrice-Visso-Norcia seismic sequence struck the Central Apennine (Italy) in 2016. Previous works brought to light how fluid movements likely triggered the sequence and reduced the stability of the normal... more
<p>The Amatrice-Visso-Norcia seismic sequence struck the Central Apennine (Italy) in 2016. Previous works brought to light how fluid movements likely triggered the sequence and reduced the stability of the normal fault network following the first earthquake (Amatrice, M<sub>w</sub>6.0), and the subsequent events of Visso (M<sub>w</sub>5.9) and Norcia (M<sub>w</sub>6.5) mainshocks.<br>Seismic attenuation has the potential to<em> </em>visualize fluids presence and fractures in a seismic sequence and to image the effect of fluid migration in the events nucleation.</p><p>This work aims to provide 3D images of scattering and absorption at different frequency bands for two datasets, one before the sequence (March 2013-August 2016) and a second from the Amatrice-Visso-Norcia sequence (August 2016-January 2017). To measure scattering and absorption we used peak delay mapping and coda-attenuation tomography, respectively.<br>Previous 2D imaging of scattering and absorption showed a difference between the pre-sequence and the singular sequences at different frequency bands. Structural discontinuities and lithology control scattering losses at all frequencies, while a single high-absorption anomaly developed NNW-SSE across the seismogenic zone during the seismic sequence, probably related to the migration of deep-CO<sub>2</sub> fluids from a deep source of trapped CO<sub>2</sub> near the Amatrice earth.<br>The 3D preliminary results<em> </em>are in agreement with the 2D mapping, with high-scattering anomalies following the main structural and lithological elements of the Central Apennines (e.g. Monti Sibillini thrust), both during the pre-sequence and the sequence, also in depth. As for the 2D, the high absorption anomaly is widespread in the area before the Amatrice event, while it is mainly focused on the seismogenic zone during the sequence. This spatial expansion can be related to the deep migration of CO<sub>2</sub>-bearing fluids across the fault network also at seismogenic depths.</p>
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eastern Turkey; causing vast damage in the cities of Van and Erciş. The mainshock was followed by a large number of aftershocks, which define a 60–70 km long and 30–35 km wide northeast–southwest-trending structure, in agreement with the... more
eastern Turkey; causing vast damage in the cities of Van and Erciş. The mainshock was followed by a large number of aftershocks, which define a 60–70 km long and 30–35 km wide northeast–southwest-trending structure, in agreement with the source rupture mod-els derived for the main event. In this paper, we take advantage of this large data set to examine the spatial and temporal properties of the Van earthquake aftershock activity. We derive the spatial distribution of b-value of the Gutenberg–Richter law, as well as com-plementary seismicity parameters, along the surface projection of the fault plane. Recent studies have been published on the same issue, presenting controversial and sometimes opposite results. With respect to previous studies, we rely on a possibly higher quality catalog of relocated earthquakes. Furthermore, we adopt a more conservative approach, excluding from the analysis the first few days of data, until theMc reaches a stable com-pleteness threshold; finally, w...
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Research Interests: Mathematics and Median
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Our results show that; The time-dependent maps differ by about 50% from the time-independent maps close to fault sources. From the traditional hazard maps we observed that the maximum PGA values associated with 10% probability of... more
Our results show that; The time-dependent maps differ by about 50% from the time-independent maps close to fault sources. From the traditional hazard maps we observed that the maximum PGA values associated with 10% probability of exceedance in 50 years vary between 0.32 g and 0.36 g in the Messina Straits and the Cosenza area while the time dependent analysis under the BPT model yields hazard results significantly lower (the absolute variation of PGA being about 0.1-0.15g) especially in the southern Calabria. This difference becomes less pronounced considering the ∆CFF effect in the same area. However, we observed that a positive effect of ∆CFF is significant for several seismogenic sources in the southern Calabria. The static stress change becomes critical when the faults close to the source under consideration produced the last event before its latest characteristic earthquake. Using the maximum values of ∆CFF, we observed that the PGA values increase around 0.1 g respect to those...
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Seismicity-based earthquake forecasting models have been primarily studied and developed over the past twenty years. These models mainly rely on seismicity catalogs as their data source and provide forecasts in time, space, and magnitude... more
Seismicity-based earthquake forecasting models have been primarily studied and developed over the past twenty years. These models mainly rely on seismicity catalogs as their data source and provide forecasts in time, space, and magnitude in a quantifiable manner. In this study, we presented a technique to better determine future earthquakes in space based on spatially smoothed seismicity. The improvement’s main objective is to use foreshock and aftershock events together with their mainshocks. Time-independent earthquake forecast models are often developed using declustered catalogs, where smaller-magnitude events regarding their mainshocks are removed from the catalog. Declustered catalogs are required in the probabilistic seismic hazard analysis (PSHA) to hold the Poisson assumption that the events are independent in time and space. However, as highlighted and presented by many recent studies, removing such events from seismic catalogs may lead to underestimating seismicity rates ...