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Preseismic and coseismic deformation associated with the Hollister, California, earthquake of November 28, 1974

Journal of Geophysical Research
By: , , and 
https://doi.org/10.1029/JB081i020p03567

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Abstract

The epicenter of the Hollister earthquake (ML = 5.1) of November 28, 1974, is located near the center of an 81‐line trilateration network which has been surveyed annually since 1971. Five lines in the neighborhood of the epicenter were surveyed just 2 days before the earthquake, and two other lines nearby were surveyed 48 days earlier. Although some of these measurements suggest a possible preearthquake anomaly in line length, the anomaly is within the uncertainty in measurement. A comparison of the most recent preearthquake survey (June 1974) and the most immediate postearthquake survey (December 1974 to January 1975) of the entire network indicates a uniform linear contraction of about 0.8 ppm. This is most reasonably attributed to survey error even though a systematic error of that magnitude is unexpected. We conclude that no demonstrable preseismic or coseismic deformation was detected and suggest that an upper limit for these phenomena is less than 1 ppm in line length. A reasonable dislocation model for the Hollister earthquake yields coseismic changes in line length not greater than a few parts in 107, well below the limit of detection in Geodolite surveys.

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Publication type Article
Publication Subtype Journal Article
Title Preseismic and coseismic deformation associated with the Hollister, California, earthquake of November 28, 1974
Series title Journal of Geophysical Research
DOI 10.1029/JB081i020p03567
Volume 81
Issue 20
Year Published 1976
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center
Description 8 p.
First page 3567
Last page 3574
Country United States
State California
City Hollister
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