Viscoelastic fault-based model of crustal deformation for the 2023 update to the U.S. National Seismic Hazard Model

Seismological Research Letters
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Abstract

The 2023 update to the National Seismic Hazard (NSHM) model is informed by several deformation models that furnish geodetically estimated fault slip rates. Here I describe a fault‐based model that permits estimation of long‐term slip rates on discrete faults and the distribution of off‐fault moment release. It is based on quantification of the earthquake cycle on a viscoelastic model of the seismogenic upper crust and ductile lower crust and mantle. I apply it to a large dataset of horizontal and vertical Global Positioning System (GPS) interseismic velocities in the western United States, resulting in long‐term slip rates on more than 1000 active faults defined for the NSHM. A reasonable fit to the GPS dataset is achieved with a set of slip rates designed to lie strictly within a priori geologic slip rate bounds. Time‐dependent effects implemented via a “ghost transient” have a profound effect on slip rate estimation and tend to raise calculated slip rates along the northern and southern San Andreas fault by up to several mm/yr.

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Publication type Article
Publication Subtype Journal Article
Title Viscoelastic fault-based model of crustal deformation for the 2023 update to the U.S. National Seismic Hazard Model
Series title Seismological Research Letters
DOI 10.1785/0220220137
Volume 93
Issue 6
Year Published 2022
Language English
Publisher Seismological Society of America
Contributing office(s) Earthquake Science Center
Description 13 p.
First page 3087
Last page 3099
Country United States
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