HR: 1340h
AN: T43A-1386    [Abstracts]
TI: Fault Detection Using Resistivity Image Profiling Method at Taoyuan and Hsinchu, Taiwan
AU: * Hsung-Chang, L
EM: ps310486@ms18.hinet.net
AU: Chieh-hou, Y
EM: yang@cyu.edu.tw
AU: Yan-hao, H
EM: u6311128@tknet.tku.edu.tw
AB: As Taiwan is located in the Neotectonic belt along the western Pacific Ocean, the detection of active faults is important for it provides the information for the analysis of earthquake risk. In addition, some active faults in Taiwan lie typically at the bases of urban or industrial area, their identifications are often challengeable because of environmental changes and interferences, etc. The Taoyuan and Hsinchu county are most important high technology sites in Taiwan. Based on previous geophysical and geologic surveys, the well-known active Hukou fault right crosses the site, although the exact location of active fault zone remains unclear. The detection of an active fault can be done by different geophysical methods. However, a successful recognition of a fault depends on the physical properties such as density contrast acoustic impedance and reisitivity contrast, etc. of the targets and its surroundings. Due to a large resistivity contrast between the hanging wall (low resistivity Choulan shale) and the footwall (high resistivity Toukoshan gravel beds) of the Hsinchen fault, geoelectrical sounding may well be one of the best ways to trace this fault. For the above reasons, the resistivity image profiling method was used to investigate the fault and to relate these resistivity measurements to the fault parameters. All of the field measurements to be discussed were made during the period of 2003 and 2004. Fifteen RIP survey lines were deployed in the study area. RIP results indicate that the thickness of the high resistivity gravel layer is increased between the northern cliff of the Hu-Kou terrace and southern edge of Yangmei graben. An obvious difference of altitude is found among low resistivity zones. It may associate with the disturbance or dislocation of layers in the past. Combined the RIP sounding results to the local topographic maps, geologic data, and formal open pits information, fault zones are being recognized. Keywords: active fault; resistivity change; Hukou fault; Taiwan
DE: 0600 ELECTROMAGNETICS
DE: 0905 Continental structures (8109, 8110)
DE: 0925 Magnetic and electrical methods (5109)
SC: Tectonophysics [T]
MN: Fall Meeting 2005