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Rupture propagation along stepovers of strike-slip faults; effects of initial stress and fault geometry

Wang Hui, Mian Liu, Benchun Duan and Cao Jianling
Rupture propagation along stepovers of strike-slip faults; effects of initial stress and fault geometry
Bulletin of the Seismological Society of America (April 2020) 110 (3): 1011-1024

Abstract

Large earthquakes on strike-slip faults often rupture multiple fault segments by jumping over stepovers. Previous studies, based on field observations or numerical modeling with a homogeneous initial stress field, have suggested that stepovers more than approximately 5 km wide would stop the propagation of rupture, but many exceptions have been observed in recent years. Here, we integrate a dynamic rupture model with a long-term fault stress model to explore the effects of background stress perturbation on rupture propagation across stepovers along strike-slip faults. Our long-term fault models simulate steady-state stress perturbation around stepovers. Considering such stress perturbation in dynamic rupture models leads to prediction of larger distance a dynamic rupture can jump over stepovers: over 15 km for a releasing stepover or 7 km for a restraining stepover, comparing with the 5 km limit in models with the same fault geometry and frictional property but assuming a homogeneous initial stress. The effect of steady-state stress perturbations is stronger in an overlapping stepover than in an underlapping stepover. The maximum jumping distance can reach 20 km in an overlapping releasing stepover with low-static frictional coefficients. These results are useful for estimating the maximum length of potential fault ruptures and assessing seismic hazard.


ISSN: 0037-1106
EISSN: 1943-3573
Coden: BSSAAP
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 110
Serial Issue: 3
Title: Rupture propagation along stepovers of strike-slip faults; effects of initial stress and fault geometry
Affiliation: China Earthquake Administration, Institute of Earthquake Forecasting, Beijing, China
Pages: 1011-1024
Published: 20200407
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 75
Accession Number: 2020-039349
Categories: SeismologyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
Secondary Affiliation: University of Missouri, USA, United StatesTexas A&M University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 202025
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