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台湾车笼埔断层钻探项目(TCDP)钻了2km深的井孔来研究1999年Mw7·6级集集地震中破裂的车笼埔断层的结构和力学状态。在500～1900m的深度进行了TCDP的地球物理测井,包括为了识别地层面的裂缝和剪切区域的双极声学成像(DSI)测井和地层精细成像(FMI)测井。根据钻孔得到的连续岩芯资料,1110m深度的剪切区域被解释为车笼埔断层,位于锦水页岩内,延伸至1013～1300m的深度。整个井孔长度范围内观测到了应力导致的钻孔崩落。这些数据表明总的应力方向(N115°E)基本平行于区域应力场,并平行于菲律宾海板块相对于欧亚板块的俯冲方向。平均应力方向的可变性在不同深度均观测到。特别是在车笼埔断层附近有一个大的应力方向异常。1000m和1310m深度的突然应力偏转接近于锦水页岩的上边界和下边界,表明分层面在集集地震中滑动的可能性。
The 2-km deep borehole was drilled at the Thangkawa cage-caving project TCDP to study the structure and mechanics of the Chekpaipu fault ruptured in the 1999 Mw7.6 earthquake. TCDP geophysical logs were conducted at depths of 500-1900 m, including bipolar acoustic imaging (DSI) logging and formation fine imaging (FMI) logging to identify formation fractures and shear zones. According to the continuous core data obtained from drilling, the shear zone at a depth of 1110 m is interpreted as a car cage fault located within the Jin Shui shale and extending to a depth of 1013 to 1300 m. Stress-induced hole collapse was observed throughout the length of the wellbore. These data show that the total stress direction (N115 ° E) is basically parallel to the regional stress field and parallel to the subducting direction of the Philippine Sea plate relative to the Eurasian plate. The variability in mean stress direction is observed at different depths. In particular, there is a large stress direction anomaly near the fault of Chengtangpu. The sudden stress deflections at depths of 1000 m and 1310 m are close to the upper and lower boundaries of the Jinshui shale, indicating the possibility of stratification sliding over the collection earthquakes.