Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Equivalent point-source modeling of moderate-to-large magnitude earthquakes and associated ground-motion saturation effects

Emrah Yenier and Gail M. Atkinson
Equivalent point-source modeling of moderate-to-large magnitude earthquakes and associated ground-motion saturation effects
Bulletin of the Seismological Society of America (June 2014) 104 (3): 1458-1478

Abstract

We modeled the source and attenuation attributes of well-recorded M6+ earthquakes based on the equivalent point-source approach, with the goal of determining how to treat ground-motion saturation effects within this context. We consider ground motions as originating from an equivalent point source and mimic finite-fault effects by treating the motion as emanating from a virtual point (not a real point on the fault rupture), such that ground motions are correctly predicted at close distances. This is achieved by using an effective distance metric R=(D (sub 2) (sub rup) +h (super 2) ) (super 0.5) , in which D (sub rup) is the closest distance to the rupture and h is a pseudodepth term that accounts for saturation effects. We found that the distance-saturation effect is magnitude dependent, extending to further distances with increasing magnitude. For earthquakes of M> or =6, we model the saturation term as log(h)=-1.72+0.43 M with a standard deviation of 0.19 in log10 units, based on the values obtained from the study earthquakes. The apparent source spectra of most M 6+ earthquakes can be modeled using a simple Brune point-source model. For a few of the M 6+ earthquakes, notably those in California, we observed a spectral sag at intermediate frequencies. For such earthquakes, a two-corner point-source model provides a better match than the Brune model. We conclude that an equivalent point-source model based on the effective distance concept can successfully predict the average ground motions from M6+ earthquakes over a wide distance range, including close distances (<20 km).


ISSN: 0037-1106
EISSN: 1943-3573
Coden: BSSAAP
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 104
Serial Issue: 3
Title: Equivalent point-source modeling of moderate-to-large magnitude earthquakes and associated ground-motion saturation effects
Affiliation: Western University, Department of Earth Sciences, London, ON, Canada
Pages: 1458-1478
Published: 201406
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 67
Accession Number: 2014-051945
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
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: 201428
Close Modal

or Create an Account

Close Modal
Close Modal