Remote triggering of microseismicity in Antarctica by large distant earthquakes

Abstract

Recent studies suggested that seismic waves from significant earthquakes could trigger shallow seismic events and deep tremor in tectonically active regions at the long-distance range. Dynamic stresses carried by teleseismic waves can promote failure on the critically stressed faults at depth and trigger local microseismicity. This phenomenon is also known as remote triggering. However, only a few remote triggering studies have been done in Antarctica, mostly due to sparse network coverage. Since 2007, a new generation of broadband sensors has been deployed as permanent stations throughout Antarctica (POLENET project). This, together with other permanent and temporary seismic stations, provides critical infrastructure to investigate the remote triggering effect in Antarctica. In this study, we examine remotely triggered seismicity following large distant mainshocks since 2000 with visual inspection on raw waveforms and spectrograms. We identify evidence of possible triggered local events at various stations during or immediately following the surface waves of the 2010 Mw8.8 Maule, 2012 Mw8.6 Indian Ocean and 2016 Mw7.8 Kaikoura earthquakes. We also focus on how large distant earthquakes since 2000 triggered seismic activity around Mt. Erebus using broadband station IU.SBA, and find an apparent triggering threshold of 4-6KPa. Besides, we examine the spatial distribution of remote triggering with tectonic background and ice movement of Antarctica. Our results are consistent with previous inferences that most triggered events occur within West Antarctica and Antarctic Peninsula with rapid glacier movement and tectonic activity as compared to stable East Antarctica.