36 Earthquake Hazards in Applied Geology (Posters)

Friday, 4 April 2025
8:00 AM - 4:00 PM
Sierra Ballroom

PALEOSEISMIC SLIP MODEL FOR THE WASATCH FAULT

Paper number: 36-2
Program: Theme Sessions
Time: 8:00 AM – 4:00 PM

Authors

Abstract

The Wasatch fault is a normal fault that stretches through all the main cities of Utah up to the lower region of Idaho. The 390 km stretch is split up into 5 segments that were originally thought to be earthquake barriers. We used paleoseismic event data to construct a rupture catalog for the Wasatch fault and test whether large, multi-segment events are required to match the observed slip rates. Slip rates for the Wasatch fault range from 1.3 to 2.0 mm/yr. We compiled Oxcal-calibrated event records for 19 paleoseismic sites, spanning up to 12 kyr before present, and used these to construct candidate event histories. Two models were then constructed: one where no ruptures breach a segment boundary, and a second where events crossed one or more segment boundaries, producing larger events with greater slip. Confining events to single segments underpredicts the required slip rate by a factor of two to three. We conclude that the majority of earthquakes must rupture more than one segment to match the observed slip rates.

Geological Society of America Abstracts with Programs. Vol. 57, No. 4

doi: 10.1130/abs/2025CD-409899

© Copyright 2025 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.