Annual Modulation of Triggered Seismicity following the 1992 Landers Earthquake in California
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.
S. S. Gao et al., "Annual Modulation of Triggered Seismicity following the 1992 Landers Earthquake in California," Nature, vol. 406, no. 6795, pp. 500-504, Nature Publishing Group, Aug 2000.
The definitive version is available at http://dx.doi.org/10.1038/35020045
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)
Article - Journal
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