A Study of Sp Converted Phase Using Strong Ground Motion Records in Kaoping Region, Taiwan

• Main Authors: Min-Han Chuang, 莊閔涵
• Other Authors: Yih-Min Wu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/02995684219179973694

碩士 === 國立臺灣大學 === 地質科學研究所 === 100 === Taiwan is located on the boundary of the Philippine Sea Plate and the Eurasian Plate with highly seismicity. Several dense seismic networks are installed in Taiwan and offer a lot of the earthquake records for related studies. The study region, the Kaoping area is a triangle alluvial plain located in the southwestern Taiwan. Accelerograms recorded from 1992 to 2010 by the Taiwan Strong Motion Instrumentation Program (TSMIP) stations are used to study the depth variation of the Sp phase converted point. There are 164 Sp converted phases picked from 104 stations with 3-D velocity model and travel-time difference of S and Sp phases to estimate the converted depth of the Sp phase. Results show that the depths of converted point increase toward the west throughout of the study region. Kaohsiung area is located in western area of Kaoping region. The average depths of converted points in Kaohsiung region is about 14 km with a deepest depth of 17 km. Three-dimensional model shows Kaoping area characterized by a low Vp and high Vp/Vs zone. These signals maybe explain the large depth in this area. These depths also can be the boundary of accretionary prism and oceanic crust in this region. The Pingtung area is located in the eastern area of the study region. The depths of converted points are from 4 to 8 km and distribute around the Wushan formation (Miocene strata). Sandstone-Shale Interface at the Wushan formation beneath the sediment may be the boundary where Sv convert to P wave in the Pingtung area.