| Summary: | 碩士 === 國立中正大學 === 地震研究所 === 106 === The Meishan fault is situated at the southwestern Taiwan, and was believed associated with the 1906 ML=7.1 Meishan earthquake. The fault was a right-lateral strike-slip fault, extended from Meishan to Minhsiung for about 13 km long, in the NE-SW direction. The Meishan fault was classified as a type one active fault. After the Meishan earthquake, many liquefaction and surface ruptures were observed west of the Minhsiung area; however whether if the Meishan fault was extended westerly was still unclear. In this study, we deployed two shallow seismic reflection lines and four active and passive multichannel surface wave analysis lines to study the relationship between the occurrence of liquefaction and the Meishan fault. We also deployed a seismic reflection line near the eastern segment of the Meishan fault to study the relationship between the subsurface structure and the surface topography.
The result shows a northward dipping reverse fault existed in between the Minhsiung and the Xingang areas. Location of the fault is coincident with the observed liquefaction zone. Since the subsurface physical properties resulted from the P- and S-waves velocity surveys were approximately invariant between the Minhsiung and the Xingang areas, those lineation of the liquefaction distributions could be related to the multi-segment faults formed of the westward extension of the Meishan fault. The fault observed in this study could be on one of the fault segments. In the eastern section of the Meishan fault, due to the fracture zone was well related to the valley area, those valleys could be resulted from the progression of the Meishan fault was proposed.
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