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Delayed triggering of microearthquakes by multiple surface waves circling the Earth

Zhigang Peng, Chunquan Wu, & Chastity Aiken

Published 2011, SCEC Contribution #1557

It is well known that direct surface waves of large earthquakes are capable of triggering shallow earthquakes and deep tremor at long-range distances. However, it is not clear whether multiple surface waves circling the Earth could also trigger/modulate seismic activities. Here we conduct a systematic search of remotely triggered microearthquakes near the Coso Geothermal Field in central California following the 2010 Mw 8.8 Chile earthquake. We find a statistically significant increase of microearthquakes in the first few hours after the Chile mainshock. These observations of apparently delayed earthquake triggering do not follow the Omori-law decay with time since the largest ML 3.5 event occurred during the large-amplitude Love waves. Instead, they are better correlated with the first three groups of multiple surface waves (G1-R1, G2-R2, and G3). Our observation provides an alternative explanation of delayed triggering of microearthquakes at long-range distances, at least in the first few hours after large earthquakes.

Citation
Peng, Z., Wu, C., & Aiken, C. (2011). Delayed triggering of microearthquakes by multiple surface waves circling the Earth. Geophysical Research Letters, 38, L04306. doi: 10.1029/2010GL046373.