USING COULOMB STRESS CHANGES AND SEISMIC SPECTRUM INTENSITIES TO EVALUATE THE SEISMIC HAZARDS OF POTENTIAL MEISHAN EARTHQUAKE IN CENTRAL TAIWAN.

The earthquake (ML5.2) occurred at Chushan town, Nantou on Nov.11, 2017 and had caused a lot of aftershocks around the hypocenter of the mainshock. The Coulomb stress changes (ΔCFSs) by the mainshock demonstrated most of the aftershocks located within the positive parts greater than 0.1 bar, revealing the aftershocks may be induced by the mainshock. After investigating the ΔCFSs at different depths, the results showed most of positive parts of ΔCFSs under depth 15km were transferred to the southeast and southwest regions. About ten days later, there were lots of earthquakes (ML 5.2~3) with depth below 15km clustered exactly in the southeast region. The southwest region nears the Meishan fault, which began as a reverse thrust slip and caused large earthquake with ML 7.0 before 110 years ago. This means the Meishan fault may be triggered by the successive earthquakes near the fault. Based on the seismic spectrum intensities, the seismic hazards by the potential Meishan earthquake are estimated. The maximal seismic intensities will occur at Chushan town and the segment of freeway 3 connects Nantou city and Chushan town have to pay more attentions. The landslides may happen at the junctions of Nantou and Yunlin counties, which great landslides had happened, when Chi-Chi earthquake (ML7.3) occurred in 1999. [ABSTRACT FROM AUTHOR]