Constraining source and path effects of large magnitude earthquakes using ground motion simulations

Bulletin of the Seismological Society of America
By: , and 

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Abstract

The purpose of this study is to use ground‐motion simulations to investigate ways in which source and path effects for large‐magnitude earthquakes can be represented in nonergodic ground‐motion models (GMMs). To achieve this, we designed a ground‐motion study in the San Francisco Bay Area that includes earthquakes with a broad range of magnitudes distributed uniformly on a fault plane, and sites covering a large range of rupture distances and azimuths. After running a large suite of kinematic simulations (magnitude 4–7), we then develop a nonergodic GMM with the simulated data. We find that trends in the within‐site residuals are affected significantly by the earthquake radiation pattern, rupture directivity, and slip patterns. Next, we modify an existing rupture directivity model to fit and remove the observed radiation pattern and rupture directivity from the residuals. We also minimize the contributions of slip patterns by averaging the within‐site residuals among multiple source realizations. Finally, after removing the source effects from the within‐site residuals, we compare the path effects computed with different magnitude groups using two approaches. The first approach only considers the small events that have the same shortest path to a site as the large events, whereas the second approach considers all small events on the fault plane. The results indicate that it is difficult to satisfactorily approximate the path effects of large events with those of small events using either approach, at least in the case of simulations.

Suggested Citation

Meng, X., Graves, R., and Goulet, C.A., 2026, Constraining source and path effects of large magnitude earthquakes using ground motion simulations: Bulletin of the Seismological Society of America, 19 p., https://doi.org/10.1785/0120250161.

ISSN: 1943-3573 (online)

Study Area

Publication type Article
Publication Subtype Journal Article
Title Constraining source and path effects of large magnitude earthquakes using ground motion simulations
Series title Bulletin of the Seismological Society of America
DOI 10.1785/0120250161
Edition Online First
Publication Date March 19, 2026
Year Published 2026
Language English
Publisher GeoScienceWorld
Contributing office(s) Earthquake Science Center
Description 19 p.
Country United States
State California
Other Geospatial Northern California
Additional publication details