Global Search of Remotely Triggered Tremors

Abstract:

Deep tectonic tremor has been observed at major plate-boundary faults around the Pacific Rim. While regular or ambient tremor occurs spontaneously or accompanies slow-slip events, tremor could be also triggered by large distant earthquakes and solid earth tides. Because triggered tremor occurs on the same fault patches as ambient tremor and is relatively easy to identify, a systematic global search of triggered tremor could help to identify physical mechanisms and necessary conditions for tremor generation. So far triggered tremor are mostly found at relatively young subduction zones, and mature strike-slip faults at transpressional tectonic settings. These include the Parkfield-Cholame section of the San Andreas Fault, the Oriente and Enriquillo-Plantain Garden Faults in the Carribbean, the Queen Charlotte-Fairweather fault system and the Denali fault in the western Canada and Alaska. Here we summarize our ongoing search for triggered tremor around the world, focusing on regions where tremor has not been observed before, but is expected based on our prior experience. These include the Zagros and Himalaya fold and thrust belts, Sumatra and Java subduction zones, as well as other fast moving convergent and strike-slip boundary faults. In addition, we plan to search for evidence of triggered tremor at intraplate regions with dense instrumentations such as Japan and China. Finally we discuss how remote triggering of tremor could help to better understand possible interactions of large distant earthquakes.