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1999年集集地震使台湾中西部褶皱逆冲带内的车笼铺逆序逆断层(简称CTF 断层)发生了破裂。该破裂的一个重要特征为:计算出的滑移量自车笼铺断层的底部至近地表,沿板块自南东向北西会聚方向,呈现由小到大接近线性增加的趋势。根据长周期和地震周期两个不同时间尺度上应力和位移的研究结果,对同震滑移分布规律的成因给出了一个新的解释模式。在最近的0．5百万年内,造山带前缘的聚合速率被前锋带3 条主要的逆断层——彰化断层(简称Ch．F断层)、车笼铺断层和双塘断层(简称Sh．F断层)——来调节。根据先前已发表的平衡地质剖面研究成果,我们估算了彰化断层和车笼铺断层分布调节5％～30％、30％～50％造山带前缘长周期的滑移量。上述长期聚合速率的差异以及震间和震后位移模拟结果表明,车笼铺断层与震间应力载荷方向斜交和彰化断层、车笼铺断层深部递增的无震蠕变,这两个因素共同影响着同震滑移独特的线性分布特征。许多早期对滑移量分布特征及其成因的解释主要考虑到了物质属性、软弱层的滑动作用、场地效应、断层几何学以及地震波动力学等因素的影响。至于各因素对滑移量分布特征的影响程度仍不太清楚。考虑到车笼铺断层倾角的影响,采用了应力集中区的动力学模型来解释同震滑移的总体分布特征。值得一提的是,最近的研究表明集集地震前应力在空间上的不均匀分布可能对同震滑移的分布起到重要的作用。地震活动性分析结果表明,历史大地震不能够解释应力分布的不均。根据我们的研究方法,认为 Oglesby和Day(2001)提出的车笼铺断层北面存在一高应力集中区,反映了因车笼铺断层斜交引起的震间耦合在纬向上的变化规律。
The 1999 earthquake caused a rupture of the car-cage reverse reverse thrust (CTF fault) in the fold-thrust belt in central-western Taiwan. An important feature of the rupture is that the calculated slip amount tends to increase linearly from small to large along the convergence direction from south to east and northwest from the bottom to the near surface of the car-cage fault. According to the research results of stress and displacement on two different time scales of long period and seismic period, a new explanation mode of the origin of the coseismic slip distribution is given. In the recent 0.5 million years, the convergence rate of the front of the orogenic belt was enhanced by three main thrust faults: the Changhua fault (Ch.F fault), the car cage fault and the Shuangtang fault (Sh. F fault) - to adjust. Based on the previously published results of the balanced geologic profile studies, we estimated the slip of the Changhwa fault and the car-cage fault zone in the long-period of 5% to 30% and 30% to 50% of the orogenic belt front. The above-mentioned long-term polymerization rates and simulations of the post-earthquake and post-earthquake displacements show that the two factors, the diagonal intersection of the car-cage fault and the inter-seismic stress load, and the Changhua and Changchun faultages, Affecting the unique linear distribution of coseismic slip. Many early interpretations of the characteristics of slip distribution and their genesis mainly take into account the influence of material properties, slip of weak layers, site effects, fault geometry and seismic wave dynamics. As for the impact of various factors on the distribution characteristics of slip is still not clear. Taking into account the influence of the car ply fault dip angle, the dynamic model of stress concentration zone is adopted to explain the general distribution of coseismic slip. It is worth mentioning that recent studies show that the spatially uneven distribution of stress before the Jiadian earthquake may play an important role in the distribution of coseismic slip. Seismicity analysis results show that historical earthquakes can not explain the uneven distribution of stress. According to our research method, it is considered that there is a high stress concentration zone to the north of the car-cage fault proposed by Oglesby and Day (2001), which reflects the latitudinal variation of the coupling due to the bias of the car-cage fault.