Localized fault-zone dilatancy and surface inelasticity of the 2019 Ridgecrest earthquakes

Nature Geoscience
By: , and 

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Abstract

Earthquakes produce a spectrum of elastic and inelastic deformation processes that are reflected across various length and time scales. While elasticity has long dominated research assumptions in active tectonics, increasing interest has focused on the inelastic characteristics of earthquakes, particularly those of the surface fault rupture zone itself, and how they relate to ground rupture hazard and the mechanics of damage zones. Here we present detailed co-seismic surface-strain analysis of the 2019 Ridgecrest, California, earthquakes. We derive three-dimensional high-resolution surface displacements from satellite optical imagery, which we then invert for the co-seismic surface-strain tensors. We show that fault-zone dilation is pervasive throughout these earthquakes and that inelastic failure is present but relatively localized (median width of 31 m). The width of the inelastic failure zone is not correlated to off-fault deformation, surface geology or displacement magnitude. Instead, the extent and kinematics of inelastic failure reflect active, mylonitic deformation of the fault damage zone that is influenced by rupture velocity and fault maturity. These results highlight how a single earthquake contributes to the long-term, permanent geologic record of faulting.


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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Localized fault-zone dilatancy and surface inelasticity of the 2019 Ridgecrest earthquakes
Series title Nature Geoscience
DOI 10.1038/s41561-020-0628-8
Volume 13
Year Published 2020
Language English
Publisher Nature
Contributing office(s) Geologic Hazards Science Center
Description 6 p.
First page 699
Last page 704
Country United States
State California
Other Geospatial Ridgecrest
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