Low-Frequency Earthquakes within Non-Volcanic Tremor in Southern Taiwan Triggered by Large Earthquakes

We used 11 low-frequency earthquakes LFEs templates triggered by the 2005 Mw8.6 Nias earthquake to detect 65 LFEs within the tremors triggered by the 2004 Mw9.0 Sumatra, the 2007 Mw8.4 Sumatra and the 2007 Mw8.1 Kuril earthquakes. We applied a matched filter technique to scan waveform data during the surface waves of the three earthquakes. From our observation, all three large mainshocks could trigger LFEs. The LFEs distribute at the depth of 10-39 km beneath the Central Range and along the steep-dipping Chaochou-Lishan fault with relatively high Vp/Vs ratios (1.75-1.85). Our observations suggest that the triggered LFEs and tremor reflect possible deep fault slips at the lowermost crust that are facilitated by elevated fluid pressures and dynamic stresses from teleseismic events.