SEISMIC HAZARD ASSESSMENT IN THE BROADER AEGEAN AREA USING TIME-INDEPENDENT SEISMICITY MODELS BASED ON SYNTHETIC EARTHQUAKE CATALOGS

In order to evaluate the seismic hazard for the broader Aegean area, a modified timeindependent seismicity model is used. A Monte-Carlo procedure has been employed to create synthetic earthquake catalogs with specific characteristics regarding their time, space and magnitude distributions. Moreover, particular geometrical characteristics, such as subducting and oblique seismic zones are also taken into account in the synthetic catalogs generation. A significantly revised earthquake catalog, all available fault plane solutions and information on the seismotectonics of the broader Aegean area were considered in order to propose a new updated model of seismic zones for this area. Seismicity parameters for the new seismic zones were calculated and the corresponding synthetic earthquake catalogs were generated using the proposed procedure. The distribution of the expected values for ground motion parameters (e.g. PGA, PGV) was estimated using synthetic catalogs for several sites of interest, by performing computations directly on all earthquakes of each catalog. Computations were performed for a dense grid of sites and seismic hazard estimates were determined both directly from the peak ground motion distribution, as well as from fitted extreme values Gumbel distribution. Ground motion parameters were also calculated using classic seismic hazard assessment algorithms (EqRISK), in order to evaluate the compatibility of the proposed method with conventional approaches.

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A detailed seismic zonation model for shallow earthquakes in the broader Aegean area

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-1-6719-2013 ◽

2013 ◽

Vol 1 (6) ◽

pp. 6719-6784 ◽

Cited By ~ 3

Author(s):

D. A. Vamvakaris ◽

C. B. Papazachos ◽

C. Papaioannou ◽

E. M. Scordilis ◽

G. F. Karakaisis

Keyword(s):

Seismic Hazard ◽

Hazard Assessment ◽

Active Faults ◽

Seismic Hazard Assessment ◽

Maximum Magnitude ◽

Seismic Zone ◽

Seismic Zonation ◽

Aegean Area ◽

Seismic Zones ◽

Shallow Earthquakes

Abstract. In the present work we present an effort to define a new seismic zonation model of area type sources for the broader Aegean area, which can be readily used for seismic hazard assessment. The definition of this model is based not only on seismicity information but incorporates all available seismotectonic and neotectonic information available for the study area, in an attempt to define zones which show not only a rather homogeneous seismicity release but also exhibit similar active faulting characteristics. For this reason, all available seismological information such as fault plane solutions and the corresponding kinematic axes have been incorporated in the analysis, as well as information about active tectonics, such as seismic and active faults. Moreover, various morphotectonic features (e.g. relief, coastline) were also considered. Finally, a revised seismic catalogue is employed and earthquake epicentres since historical times (550 BC–2008) are considered, in order to define areas of common seismotectonic characteristics, that could constitute a discrete seismic zone. A new revised model of 113 earthquake seismic zones of shallow earthquakes for the broader Aegean area is finally proposed. Using the proposed zonation model, a detailed study is performed for the catalogue completeness for the recent instrumental period. Using the defined completeness information, seismicity parameters (such as G–R values) for the 113 new seismic zones have been calculated, and their spatial distribution was also examined. The spatial variation of the obtained b values shows an excellent correlation with the geotectonic setting in the area, in good agreement with previous studies. Moreover, a quantitative estimation of seismicity is performed in terms of the mean return period, Tm, of large (M ≥ 6.0) earthquakes, as well as the most frequent maximum magnitude, Mt, for a typical time period (T = 50 yr), revealing significant spatial variations of seismicity levels within the study area. The new proposed seismic zonation model and its parameters can be readily employed for seismic hazard assessment for the broader Aegean area.

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A detailed seismic zonation model for shallow earthquakes in the broader Aegean area

Natural Hazards and Earth System Science ◽

10.5194/nhess-16-55-2016 ◽

2016 ◽

Vol 16 (1) ◽

pp. 55-84 ◽

Cited By ~ 10

Author(s):

D. A. Vamvakaris ◽

C. B. Papazachos ◽

Ch. A. Papaioannou ◽

E. M. Scordilis ◽

G. F. Karakaisis

Keyword(s):

Seismic Hazard ◽

Hazard Assessment ◽

Active Faults ◽

Seismic Hazard Assessment ◽

Maximum Magnitude ◽

Seismic Zone ◽

Seismic Zonation ◽

Aegean Area ◽

Seismic Zones ◽

Shallow Earthquakes

Abstract. In the present work we propose a new seismic zonation model of area type sources for the broader Aegean area, which can be readily used for seismic hazard assessment. The definition of this model is based not only on seismicity information but incorporates all available seismotectonic and neotectonic information for the study area, in an attempt to define zones which show not only a rather homogeneous seismicity release but also exhibit similar active faulting characteristics. For this reason, all available seismological information such as fault plane solutions and the corresponding kinematic axes have been incorporated in the analysis, as well as information about active tectonics, such as seismic and active faults. Moreover, various morphotectonic features (e.g. relief, coastline) were also considered. Finally, a revised seismic catalogue is employed and earthquake epicentres since historical times (550 BC–2008) are employed, in order to define areas of common seismotectonic characteristics, that could constitute a discrete seismic zone. A new revised model of 113 earthquake seismic zones of shallow earthquakes for the broader Aegean area is finally proposed. Using the proposed zonation model, a detailed study is performed for the catalogue completeness for the recent instrumental period.Using the defined completeness information, seismicity parameters (such as G–R values) for the 113 new seismic zones have been calculated, and their spatial distribution was also examined. The spatial variation of the obtained b values shows an excellent correlation with the geotectonic setting in the area, in good agreement with previous studies. Moreover, a quantitative estimation of seismicity is performed in terms of the mean return period, Tm, of large (M  ≥  6.0) earthquakes, as well as the most frequent maximum magnitude, Mt, for a typical time period (T  =  50 yr), revealing significant spatial variations of seismicity levels within the study area. The new proposed seismic zonation model and its parameters can be readily employed for seismic hazard assessment for the broader Aegean area.

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Discussion on the influence of truncation of ground motion residual distribution on probabilistic seismic hazard assessment

Earthquake Engineering and Engineering Vibration ◽

10.1007/s11803-011-0074-0 ◽

2011 ◽

Vol 10 (3) ◽

pp. 379-392 ◽

Cited By ~ 5

Author(s):

Jian Wu ◽

Mengtan Gao ◽

Kun Chen ◽

Bei Huang

Keyword(s):

Seismic Hazard ◽

Ground Motion ◽

Hazard Assessment ◽

Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard ◽

Residual Distribution

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Simulation-Based Seismic Hazard Assessment Using Monte-Carlo Earthquake Catalogs: Application to CyberShake

Bulletin of the Seismological Society of America ◽

10.1785/0120200375 ◽

2021 ◽

Author(s):

Sarah Azar ◽

Mayssa Dabaghi

Keyword(s):

Monte Carlo ◽

Seismic Hazard ◽

Ground Motion ◽

Seismic Hazard Assessment ◽

Computational Time ◽

Earthquake Catalog ◽

Earthquake Catalogs ◽

Earthquake Scenarios ◽

Simulation Based ◽

Hazard Curves

ABSTRACT The use of numerical simulations in probabilistic seismic hazard analysis (PSHA) has achieved a promising level of reliability in recent years. One example is the CyberShake project, which incorporates physics-based 3D ground-motion simulations within seismic hazard calculations. Nonetheless, considerable computational time and resources are required due to the significant processing requirements imposed by source-based models on one hand, and the large number of seismic sources and possible rupture variations on the other. This article proposes to use a less computationally demanding simulation-based PSHA framework for CyberShake. The framework can accurately represent the seismic hazard at a site, by only considering a subset of all the possible earthquake scenarios, based on a Monte-Carlo simulation procedure that generates earthquake catalogs having a specified duration. In this case, ground motions need only be simulated for the scenarios selected in the earthquake catalog, and hazard calculations are limited to this subset of scenarios. To validate the method and evaluate its accuracy in the CyberShake platform, the proposed framework is applied to three sites in southern California, and hazard calculations are performed for earthquake catalogs with different lengths. The resulting hazard curves are then benchmarked against those obtained by considering the entire set of earthquake scenarios and simulations, as done in CyberShake. Both approaches yield similar estimates of the hazard curves for elastic pseudospectral accelerations and inelastic demands, with errors that depend on the length of the Monte-Carlo catalog. With 200,000 yr catalogs, the errors are consistently smaller than 5% at the 2% probability of exceedance in 50 yr hazard level, using only ∼3% of the entire set of simulations. Both approaches also produce similar disaggregation patterns. The results demonstrate the potential of the proposed approach in a simulation-based PSHA platform like CyberShake and as a ground-motion selection tool for seismic demand analyses.

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