Reactivation of the Shanchiao Fault and its Implication to the Variation of Landforms in Taipei Basin
Date Issued
2007
Date
2007
Author(s)
Chiu, Chun-Ying
DOI
zh-TW
Abstract
The Shanchiao fault, located in west of the Taipei basin, is a highly active normal fault with minor left-slip component. The fault length is over 40 km. Due to the movement of Shanchiao fault, the depth of Tertiary basement in the Taipei Basin is at least 700 m. We suggest that the Shanchiao fault still has the ability to induce subsidence in the Taipei Basin under present extensional regime of northern Taiwan. In order to discuss the co-seismic ground deformation, we model the behavior of earthquakes along the Shanchiao fault with the dislocation model. In this study, we also construct the three dimensional fault plane of the Shanchiao fault and we suggest that the fault has the larger slip around the Kuandu area. When seismic moment-magnitude reaches 6.5, the footwall of Shanchiao fault could subside over 1 m and when seismic moment-magnitude reaches 7.0, the area that subsides over 1 m could reaches 115 Km2. After comparing the model result with the record of prehistoric earthquakes along the Shanchiao fault and the depth of Tertiary basement, we suppose that the seismism of Shanchiao fault should have left-lateral slip portion and it was more active in the north fault section in the Taipei basin. Finally, we discuss the influences of inundation with the variant landforms in two situation : The break of embankment and heavy rainfall. The predicted area subsides below sea level is about 40 Km2 when a moment-magnitude 7 earthquake occurs along the Shanchiao fault. The region, spreads around Sinjhuang, Wugu, Lujhou and Guandu could be submerged by flood. However, the pattern of inundation that results from heavy rainfall may change because the relatively low region changes after earthquake.
Subjects
山腳斷層
台北盆地
錯位模擬
地表同震變形
淹水模式分析
Shanchiao Fault
Taipei Basin
dislocation model
coseismic deformation
inundation model
Type
thesis
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