Comparisons of dynamic triggering near Beijing, China following recent large earthquakes in Sumatra

Abstract

Dynamic triggering around the Fangshan Pluton near Beijing is repeatedly identified. Here we report clear triggered events in this region during the surface waves of the 2012 Mw8.6 Sumatra earthquake. However, we do not find any triggered events during the G2 waves of the Mw8.6 event, and the surface waves of the Mw8.2 Sumatra earthquake that occurred two hours later. The peak ground velocities of the 2012 Mw8.2 event are around the apparent triggering threshold of 0.1–0.2 cm/s in this region. Hence, the fact that this event did not trigger does not require an influence of elapsed time since last trigger (the Mw8.6 mainshock), but is consistent with it. The lack of triggering during the G2 wave of the 2012 Mw8.6 mainshock may be caused by relatively weak surface‐wave signals in the intermediate period of 100–10 s.