Local near-instantaneously dynamically triggered aftershocks of large earthquakes

Wenyuan Fan, & Peter M. Shearer

Submitted July 30, 2016, SCEC Contribution #6414, 2016 SCEC Annual Meeting Poster #173

Aftershocks are often triggered by static- and/or dynamic-stress changes caused by mainshocks. The relative importance of the two triggering mechanisms is controversial at near-to-intermediate distances. We detect and locate 48 previously unidentified large early aftershocks triggered by 7 <= M < 8 earthquakes within a few fault lengths (~300 km), during times that high-amplitude surface waves arrive from the mainshock (< 200 s). The observations indicate that near-to-intermediate field dynamic triggering commonly exists and fundamentally promotes aftershock occurrence. The mainshocks and their nearby early aftershocks are located at major subduction zones and continental boundaries, and mainshocks with all types of faulting-mechanisms (normal, reverse, and strike-slip) can trigger early aftershocks.

Fan, W., & Shearer, P. M. (2016, 07). Local near-instantaneously dynamically triggered aftershocks of large earthquakes. Poster Presentation at 2016 SCEC Annual Meeting.

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