Annual Modulation of Triggered Seismicity following the 1992 Landers Earthquake in California

Abstract

The mechanism responsible for the triggering of earthquakes remains one of the least-understood aspects of the earthquake process. The magnitude-7.3 Landers, California earthquake of 28 June 1992 was followed for several weeks by triggered seismic activity over a large area, encompassing much of the western United States. Here we show that this triggered seismicity marked the beginning of a five-year trend, consisting of an elevated microearthquake rate that was modulated by an annual cycle, decaying with time. The annual cycle is mainly associated with several hydrothermal or volcanic regions where short-term triggering was also observed. These data indicate that the Landers earthquake produced long-term physical changes in these areas, and that an environmental source of stress - plausibly barometric pressure - might be responsible for the annual variation.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

earthquake mechanism; geobarometry; Landers earthquake 1992; seismicity; earthquake; periodicity; United States

International Standard Serial Number (ISSN)

0028-0836

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2000 Nature Publishing Group, All rights reserved.

Publication Date

01 Aug 2000

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