Seismic observation of the foothills of the Pingtung area

• Main Authors: Li-Chun Hu, 胡立群
• Other Authors: Horng-Yuan Yen
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/51924952547189820066

碩士 === 國立中央大學 === 地球物理研究所 === 91 === The Chaochou fault in the Pingtung area is one of the most important faults in southern Taiwan, and is located between the Pingtung Plain and the Central Range. According to previous studies, the Chaochou fault is considered to be a high-angle fault that dips eastward to the Central Range. From a tectonic point of view, regional stresses in the Pingtung area are controlled by two tectonic forces. The first force is the compressional stress related to the arc-continent collision between the Philippine Sea Plate and the Eurasian Plate; the second is the extensional stress related to the opening of the South China Sea to the South. Under these two mechanisms, the crustal structure beneath the Pingtung area has a complex formation. However, in examining earthquakes greater than magnitude 3 that occurred in the years between 1991 and 2001, we discover that the seismicity in southwestern Taiwan in this period was low. The question as to why this is the case is what first inspired our interest in studying this particular area. This study makes use of data collected by the Institute of Earth Sciences, Academia Sinica between August 2001 and January 2002 at 24 temporary seismic stations located near the Chaochou fault, as well as velocity structures collected through tomography in the foothills of the Pingtung area. We hope that this study will teach us more about crustal structure of this area and will enable us to understand the reasons for low seismicity there.