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Probabilistic estimates of surface coseismic slip and afterslip for Hayward fault earthquakes

Bulletin of the Seismological Society of America

By:
, ,
DOI: 10.1785/0120110200

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Abstract

We examine the partition of long‐term geologic slip on the Hayward fault into interseismic creep, coseismic slip, and afterslip. Using Monte Carlo simulations, we compute expected coseismic slip and afterslip at three alinement array sites for Hayward fault earthquakes with nominal moment magnitudes ranging from about 6.5 to 7.1. We consider how interseismic creep might affect the coseismic slip distribution as well as the variability in locations of large and small slip patches and the magnitude of an earthquake for a given rupture area. We calibrate the estimates to be consistent with the ratio of interseismic creep rate at the alinement array sites to the geologic slip rate for the Hayward fault. We find that the coseismic slip at the surface is expected to comprise only a small fraction of the long‐term geologic slip. The median values of coseismic slip are less than 0.2 m in nearly all cases as a result of the influence of interseismic creep and afterslip. However, afterslip makes a substantial contribution to the long‐term geologic slip and may be responsible for up to 0.5–1.5 m (median plus one standard deviation [S.D.]) of additional slip following an earthquake rupture. Thus, utility and transportation infrastructure could be severely impacted by afterslip in the hours and days following a large earthquake on the Hayward fault that generated little coseismic slip. Inherent spatial variability in earthquake slip combined with the uncertainty in how interseismic creep affects coseismic slip results in large uncertainties in these slip estimates.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Probabilistic estimates of surface coseismic slip and afterslip for Hayward fault earthquakes
Series title:
Bulletin of the Seismological Society of America
DOI:
10.1785/0120110200
Volume
102
Issue:
3
Year Published:
2012
Language:
English
Publisher:
Seismological Society of America
Contributing office(s):
Earthquake Science Center
Description:
19 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
961
Last page:
979
Country:
United States
State:
California
Other Geospatial:
Hayward Fault