Constructing subsurface structures of the Chelungpu fault to investigate mechanisms leading to abnormally large ruptures during the 1999 Chi‐Chi earthquake, Taiwan
Constructing subsurface structures of the Chelungpu fault to investigate mechanisms leading to abnormally large ruptures during the 1999 Chi‐Chi earthquake, Taiwan
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DOI：
10.1029/2003gl018323
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发表时间：
2004-01
影响因子：
5.2
通讯作者：
C. Wang;Chien-Li Li-Chien-Li-Li-120670488;Hsiang-Chun Lee
中科院分区：
文献类型：
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作者：
C. Wang;Chien-Li Li-Chien-Li-Li-120670488;Hsiang-Chun Lee
车龙埔断裂是一条南北向的逆冲断裂，在1999年台湾集集7.6级地震中被激活。在其北端，断裂转向东，造成额外的15公里的EW向分支，该分支经历了9m的异常地表破裂。本文利用浅层反射地震对地下构造进行了研究，试图找出该构造与大破裂的关系。90多条短地震线分布在10公里×20公里的区域内。用井资料仔细编制所有地震剖面，就可以构造出近似的三维地下结构。揭示的构造样式表明，车龙堡断裂滑动的关键层位金水页岩向北上升，在EW向支下变得相当浅。这种构造变化被认为是导致车龙堡断裂异常破裂的主要因素。
The Chelungpu fault, a NS oriented thrust fault, was activated by the 1999 Chi‐Chi earthquake (Mw = 7.6), Taiwan. At its northern end, the fault turned east causing an extra 15 km EW branch, which experienced abnormal 9 m surface rupturing. In this paper, we used shallow reflection seismics to investigate the subsurface structure, attempting to find the relationship between the structure and large ruptures. Over 90 short seismic lines were distributed throughout a 10 km × 20 km area. Approximate 3D subsurface structures can be constructed by carefully compiling all seismic profiles with well data. The revealed structural pattern shows that the Chinshui shale, the key‐bed layer on which the Chelungpu fault slips, arises toward the north and becomes quite shallow under the EW branch. This structural variation is believed to be the main factor causing the abnormal rupturing of the Chelungpu fault.