Isolated regions of remote triggering in South/Southeast Asia following the 2012 Mw 8.6 Indian Ocean earthquake

Abstract

Large earthquakes are capable of triggering either shallow earthquakes or deep tectonic tremors at long-range distances. So far, most of remotely triggered tremors were found along major plate boundary faults around the Pacific Rim. Here we conduct a systematic search for remotely triggered earthquakes and tremors in South/Southeast Asia following the 11 April 2012 Mw 8.6 Indian Ocean earthquake. We find additional evidence of triggered tectonic tremors beneath the Java Island and the Sulabes Island in Eastern Indonesia and triggered earthquakes in Vietnam. Tremors mostly occurred during the large-amplitude Rayleigh waves of the Indian Ocean main shock and were also triggered by several other large distant earthquakes. Although we are unable to locate them, they were recorded at stations close to major tectonic faults, suggesting that they are likely of tectonic origin. However, we find no evidence of triggered tremor/earthquakes along the Sumatra subduction zone and eastern portion of Himalaya frontal thrusts, indicating that remote triggering was not as widespread as previously thought.