Late Breaking Session: Ten-Million Years of Deformation along the Eastern California Shear Zone: Context and Characterization of the July 2019 Mw7.1 Ridgecrest Earthquake (Posters)

Sunday, 22 September 2019
8:00 AM - 12:00 PM
Special Presentation Area Hall A, North Building

HOW 1000 YEARS OF EARTHQUAKES HAVE SHAPED THE STRESS DISTRIBUTION IN THE EASTERN CALIFORNIA SHEAR ZONE: SEISMIC HAZARDS BEFORE AND AFTER THE 2019 RIDGECREST EARTHQUAKE SEQUENCE

Program: Late Breaking
Time: 10:15 AM – 10:30 AM

Authors

Abstract

The 2019 Ridgecrest earthquake sequence took place on strike-slip faults in an area where recent studies on cumulative (coseismic plus postseismic) Coulomb stress change (ΔCFS) indicate an increase in stress on faults with this kinematics. The occurrence of these earthquakes thus supports the hypothesis that the spatial and temporal distribution of major earthquakes in this region is controlled to a significant extent by the location and timing of past events. The stress changes produced by the 2019 earthquakes should then tell us which other faults in the Eastern California Shear Zone (ECSZ) may have been brought closer to failure.

In order to identify such faults, we first create a 3D model of all the faults involved. We then model the stress history in the ECSZ by calculating the cumulative ΔCFS due to several M ≥ 7 earthquakes that occurred in the ECSZ and surrounding region in the last ~1000 years, up to and including the 2019 Ridgecrest earthquake sequence. We focus specifically on the southern Sierra Nevada fault zone, Garlock fault, and Blackwater fault, but also consider stress changes to the southern part of the Owens Valley fault, and to several other normal faults in the area.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-342020

© Copyright 2019 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.