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Ground-motion variability for single site and single source through deterministic stochastic method simulations; implications for PSHA

Maria D'Amico, Mara Monica Tiberti, Emiliano Russo, Francesca Pacor and Roberto Basili
Ground-motion variability for single site and single source through deterministic stochastic method simulations; implications for PSHA
Bulletin of the Seismological Society of America (April 2017) 107 (2): 966-983

Abstract

The ground-motion median and standard deviation of empirical ground-motion prediction equations (GMPEs) are usually poorly constrained in the near-source region due to the general lack of strong-motion records. Here we explore the use of a deterministic-stochastic simulation technique, specifically tailored to reproduce directivity effects, to evaluate the expected ground motion and its variability at a near-source site, and seek a strategy to overcome the known GMPEs limitations. To this end, we simulated a large number of equally likely scenario events for three earthquake magnitudes (M (sub w) 7.0, 6.0, and 5.0) and various source-to-site distances. The variability of the explored synthetic ground motion is heteroscedastic, with smaller values for larger earthquakes. The standard deviation is comparable with empirical estimates for smaller events and reduces by 30%-40% for stronger earthquakes. We then illustrate how to incorporate directivity effects into probabilistic seismic-hazard analysis (PSHA). This goal is pursued by calibrating a set of synthetic GMPEs and reducing their aleatory variability ( approximately 50%) by including a predictive directivity term that depends on the apparent stress parameter obtained through the simulation method. Our results show that, for specific source-to-site configurations, the nonergodic PSHA is very sensitive to the additional epistemic uncertainty that may augment the exceedance probabilities when directivity effects are maximized.The proposed approach may represent a suitable way to compute more accurate hazard estimates. Electronic Supplement: Histograms of synthetic peak ground accelerations (PGAs) and peak ground velocities (PGVs).


ISSN: 0037-1106
EISSN: 1943-3573
Coden: BSSAAP
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 107
Serial Issue: 2
Title: Ground-motion variability for single site and single source through deterministic stochastic method simulations; implications for PSHA
Affiliation: Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Milano, Milan, Italy
Pages: 966-983
Published: 201704
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 73
Accession Number: 2017-037587
Categories: SeismologyEnvironmental geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch maps
N38°00'00" - N40°00'00", E15°00'00" - E17°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201721
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