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>In-situ stress at the northern portion of the Chelungpu fault, Taiwan, estimated on boring cores recovered from a 2-km-deep hole of TCDP
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In-situ stress at the northern portion of the Chelungpu fault, Taiwan, estimated on boring cores recovered from a 2-km-deep hole of TCDP
We have investigated the depth variation in the stress state at the northern part of the Chelungpu fault, Taiwan, which slipped during the 1999 Chi-Chi earthquake ( M w 7.6). In-situ stress around the fault was estimated based on the stress memory of rocks recovered from five depths (739-1316 m) of a 2-km-deep-hole. The borehole intersects a fault zone at a depth of 1111 m (FZ1111), which is the best candidate for the Chelungpu fault. Our main results are: (1) the S Hmax direction is parallel to the slip for the Chi-Chi earthquake and agrees with those of the local, regional, or tectonic scales estimated from various stress indicators; (2) significant aspects of the stress field are identical to those of paleostress; (3) the horizontal differential stress was significantly reduced just above FZ1111, which may be attributable to the existence of a significantly deformable zone at this depth.
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机译:我们调查了台湾切龙埔断裂北部的应力状态的深度变化,该断裂在1999年的集集地震(M w SUB> 7.6)期间发生了滑动。断层周围的原地应力是根据从2 km深孔的5个深度(739-1316 m)采出的岩石的应力记忆来估算的。钻孔与断层带相交的深度为1111 m(FZ1111),这是切隆普断层的最佳选择。我们的主要结果是:(1)S H max SUB> SUB>方向与集集地震的滑动方向平行,并且与当地,区域或构造的方向一致根据各种压力指标估算的量表; (2)应力场的重要方面与古应力相同; (3)在FZ1111之上,水平差应力显着降低,这可能是由于在该深度存在明显的可变形区域所致。
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