scholarly journals Tectonic styles of expected earthquakes in Italy as an input for seismic hazard modeling

2020 ◽  
Author(s):  
Silvia Pondrelli ◽  
Francesco Visini ◽  
Andrea Rovida ◽  
Vera D'Amico ◽  
Bruno Pace ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Moment ◽  
Outer Part ◽  
Seismic Hazard Assessment ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Seismic Zone ◽  
Moment Tensors ◽  
Area Source ◽  
Tectonic Style

Abstract. Tectonic styles and distributions of nodal planes are an essential input for probabilistic seismic hazard assessment. As a part of a recent elaboration of a new seismic hazard model for Italy, we adopted a cascade criteria approach to parametrize the tectonic style of expected earthquake ruptures and their uncertainty in an area-based seismicity model. Using available or recomputed seismic moment tensors for relevant seismic events (Mw starting from 4.5), first arrival focal mechanisms for less recent earthquakes, and also geological data on past activated faults, we collected a database for the last ~ 100 yrs gathering a thousand of data all over the Italian peninsula and regions around it. The adopted procedure consists, in each seismic zone, of separating the available seismic moment tensors in the three main tectonic styles, making summation within each group, identifying possible nodal plane(s) taking into account the different percentages of tectonic styles and including, where necessary, total or partial random source contributions. Referring to the used area source model, for several seismic zones we obtained robust results, e.g. along the southern Apennines we expect future earthquakes to be mostly extensional, although in the outer part of the chain strike-slip events are possible. In the Northern part of the Apennines we also expect different tectonic styles for different hypocentral depths. In zones characterized by a low seismic moment release, the possible tectonic style of future earthquakes is less clear and it has been represented using different combination (total or partial) of random sources.

scholarly journals Style of faulting of expected earthquakes in Italy as an input for seismic hazard modeling

2020 ◽  
Vol 20 (12) ◽  
pp. 3577-3592
Author(s):  
Silvia Pondrelli ◽  
Francesco Visini ◽  
Andrea Rovida ◽  
Vera D'Amico ◽  
Bruno Pace ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Moment ◽  
Outer Part ◽  
Seismic Hazard Assessment ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Seismic Zone ◽  
Moment Tensors ◽  
Area Source ◽  
Seismic Moment Release

Abstract. The style of faulting and distributions of nodal planes are essential input for probabilistic seismic hazard assessment. As part of a recent elaboration of a new seismic hazard model for Italy, we defined criteria to parameterize the styles of faulting of expected earthquake ruptures and to evaluate their representativeness in an area-based seismicity model. Using available seismic moment tensors for relevant seismic events (Mw≥4.5), first arrival focal mechanisms for less recent earthquakes, and also geological data on past activated faults, we collected a database for the last ∼100 years by gathering a thousand data points for the Italian peninsula and regions around it. In this dataset, we adopted a procedure that consists, in each seismic zone, of separating the available seismic moment tensors into the three main tectonic styles, making a summation within each group, identifying possible nodal plane(s), taking into account the different percentages of styles of faulting, and including where necessary total or partial (even in terms of tectonic style) random source contributions. Referring to the area source model used, for several seismic zones we obtained robust results; e.g., along the central and southern Apennines we expect future earthquakes to be mostly extensional, although in the outer part of the chain reverse and strike-slip events are possible. In the northern part of the Apennines we expect different styles of faulting for different hypocentral depths. In zones characterized by a low seismic moment release, the possible style of faulting of future earthquakes is less clear and it has been represented using different combinations of random sources. The robustness of our results is confirmed when compared with recent relevant earthquakes occurring in Italy.

A probabilistic seismic hazard assessment for the Turkish territory—part I: the area source model

2016 ◽  
Vol 16 (8) ◽  
pp. 3367-3397 ◽  
Author(s):  
Karin Sesetyan ◽  
Mine B. Demircioglu ◽  
Tamer Y. Duman ◽  
Tolga Çan ◽  
Senem Tekin ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Area Source ◽  
Area Source Model

scholarly journals Probabilistic seismic hazard assessment for Bayankhongor aimag of Mongolia

2019 ◽  
pp. 43-56
Author(s):  
Ankhtsetseg D ◽  
Odonbaatar Ch ◽  
Mоngоnsuren D ◽  
Bayarsaikhan E ◽  
Dembereldulam M
Keyword(s):  
Seismic Hazard ◽  
Central Asia ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Active Regions ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Probability Of Exceedance ◽  
Area Source

Central Asia is one of the seismically most active regions in the world. Its complex seismicity is due to the collision of the Eurasian and Indian plates, which has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events.The GSHAP project, aiming at hazard assessment on a global scale, indicates that the territory of Bayankhongor aimag, Mongolia, in Central Asia is characterized by maximum bedrock peak ground accelerations for 10% probability of exceedance in 50 years as medium as in range of 80 to 160cm/s2. In this study, which has been carried out within the framework of the project “Seismic microzoning map of center of 12 aimags, Mongolia”, the area source model and different kernel approaches are used for a probabilistic seismic hazard assessment for the Mongolia. The seismic hazard is assessed considering shallow (depth <50 km) seismicity only and employs an updated (with respect to previous projects) earthquake catalogue for the region. The hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the Open Deterministic and Probabilistic Seismic Hazard Assessment (ODPSHA), which is based on the Cornell methodology. The maximum hazard observed in the region reaches 93-98 cm/s2 , which in intensity corresponds to VII in MSK64 scale in the centre of Bayankhongor aimag for 475 years mean return period.

scholarly journals Active fault characterization and seismotectonic zoning of the Hispaniola island

2021 ◽  
Author(s):  
Monique Terrier-Sedan ◽  
Didier Bertil
Keyword(s):  
Dominican Republic ◽  
Seismic Hazard ◽  
Subduction Zones ◽  
Active Faults ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Seismic Zone ◽  
Seismotectonic Map

AbstractDesigning a seismic source model based on the most complete description of potentially active faults and on the kinematics of their latest movements is an essential requirement in seismic hazard studies, at regional and local scales. A study to characterize active faults in the Hispaniola island (today’s Haiti and Dominican Republic) has been conducted in the framework of the probabilistic seismic hazard assessment for Santo Domingo (capital of the Dominican Republic). In this work, we present a seismotectonic map of Hispaniola and its surroundings, based on a compilation and synthesis of geological, geophysical, geodetic and seismological data. Based on these data, distinct seismic zone sources are proposed and classified as either intercrustal domains, major active faults or subduction zones. Each seismic source is described according to several parameters, including its mechanism and current rate of deformation, the associated seismicity and its estimated maximal magnitude. These results constitute an essential database for a homogeneous evaluation of the seismic hazards of Hispaniola.

Identifying the main factors that control Probabilistic Seismic Hazard Assessment (PSHA) in the Aegean area: Results from OFAT (One Factor at A Time) analysis

2021 ◽  
Author(s):  
Athanasia Kerkenou ◽  
Constantinos Papazachos ◽  
Basil Margaris ◽  
Christos Papaioannou
Keyword(s):  
Seismic Hazard ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Critical Factors ◽  
Time Analysis ◽  
Aegean Area ◽  
Seismicity Parameters ◽  
Main Factors

&lt;p&gt;The broader Aegean area is one of the highest seismicity regions in Europe, with almost half of the European seismicity released in this region, often with damaging mainshocks, such as the recent &lt;strong&gt;M&lt;/strong&gt;7.0 Samos event. While several Probabilistic Seismic Hazard Assessment (PSHA) studies have been performed for this area, an attempt to quantify the main factors controlling PSHA has not been performed. To study the effect that each input factor (seismic source model, GMPE, seismicity parameters, etc.) has on the seismic hazard calculations, an &lt;strong&gt;OFAT&lt;/strong&gt; (One Factor at A Time) analysis has been conducted. For this analysis we considered two standard peak ground motion parameters, PGA and PGV, for a typical PSHA scenario, namely 10% probability of exceedance for a mean return period of 50 years (equivalent to a 476 yr return period). For the analysis the following factors were considered: a) Four (4) seismicity area-type source models for the broader Aegean area (Papazachos, 1990; Papaioannou and Papazachos, 2000; Woessner et al., 2015; Vamvakaris et al., 2016), as well as various uncertainties for the associated G-R seismicity parameters and active fault geometries of each seismic source, b) ten (10) Ground Motion Prediction Equations (GMPEs), which contain four NGA-West2 (Abrahamson et al., 2014; Boore et al., 2014; Campbell and Bozorgnia, 2014; Chiou and Youngs, 2014), two European (Bindi et al., 2011; Cauzzi and Faccioli, 2008) and four &amp;#8220;Greek&amp;#8221; (Theodulidis and Papazachos, 1992; Skarlatoudis et al., 2003; Danciu and Tselentis, 2007; Chousianitis et al., 2018) equations, as well as a variable number of sigma for each equation and, c) the minimum (Mmin) and maximum (Mmax) source magnitude of each seismic source. Tornado diagrams (Howard, 1988) were generated for 42 selected sites of seismological interest that span the study area, allowing to explore the extent of each factor&amp;#8217;s effect on the PSHA results. The sensitivity analysis results suggest that the GMPE selection, as well as uncertainties in the G-R parameters &lt;strong&gt;a&lt;/strong&gt; and &lt;strong&gt;b&lt;/strong&gt; are the most critical factors, significantly affecting the PGA/PGV levels for all sites. They also reveal a strong correlation of PSHA sensitivity with other seismicity parameters. For example, the employed source model and Mmax play a more critical role for regions of low seismicity, while the least important factor is the selected Mmin. The spatial distribution of the PSHA sensitivity on the various factors considered was also examined through the generation of several maps, exposing regions of high and of low PSHA uncertainty. The results can be efficiently employed by scientists and engineers in order to focus research and application efforts for a targeted uncertainty minimization of the most critical factors (which may not be the same for all sub-regions of the examined Aegean area), as well as to evaluate the reliability and uncertainty of the current PSHA estimates that are employed in seismic design.&lt;/p&gt;

The Spectral Source Model: A Tool for Deterministic and Probabilistic Seismic Hazard Assessment

1998 ◽  
Vol 14 (1) ◽  
pp. 35-57 ◽  
Author(s):  
Catherine Berge ◽  
André Herrero ◽  
Pascal Bernard ◽  
Myriam Bour ◽  
Pascal Dominique
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Broad Band ◽  
Seismic Hazard Assessment ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Data Set ◽  
Probabilistic Study ◽  
As Stress ◽  
Station Location

Seismic-hazard assessment at small scales requires the computation of realistic broad-band accelerograms near the sources. Methods that use only natural records are often limited because of the limited data set. Among recently developed methods for source modelling, the spectral-source model, based on the k−2 dislocation distribution seems particularly promising as it enables computation of synthetics for any source-receiver distance and directivity configuration. The spectral model takes into account important source characteristics, such as stress drop and directivity effects predicting acceptable high-frequency levels, whatever the station location (Bernard et al., 1996b). Firstly, some tests to explain the directivity properties of the model are presented, followed by the main results of a deterministic study carried out for the 1992 Erzincan earthquake, Turkey. Finally, results of a probabilistic study in the Moyenne-Durance region (France) are used to demonstrate the ability of this method to produce seismic-hazard maps and spectra linked to a specific return period.

Probabilistic Seismic Hazard Assessment of Sudan and Its Vicinity

2001 ◽  
Vol 17 (3) ◽  
pp. 399-415 ◽  
Author(s):  
Jamal A. Abdalla ◽  
Yahia E-A. Mohamedzein ◽  
A. Abdel Wahab
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Activity ◽  
Probabilistic Approach ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Probabilistic Seismic Hazard Assessment ◽  
Seismic Zone ◽  
Ground Acceleration ◽  
Grid Points

This paper presents seismic hazard assessment and seismic zoning of Sudan and its vicinity based on probabilistic approach. The area studied lies between 22° E- 45° E and 0° - 24° N. Tectonics of Sudan and its vicinity is first reviewed. An updated NOAA catalogue, containing both historical and instrumental events and covering the period from 700 A.D. to 1993 is then used. Seismic source regions are modeled and relationships between earthquake magnitude and earthquake frequency are established. A modified attenuation relation is used. Seismic hazard assessment is then carried out for 60 km interval grid points. Seismic hazard maps of the studied area based on peak ground acceleration (PGA) for 10% probability of exceedance for time-spans of 50, 100, 200 and 250 years are presented. The results showed that the PGA ranges from 0.02g for low seismic activity regions to around 0.62g for high seismic activity regions. A seismic zone map is also shown for 475 years return period.

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