论文部分内容阅读
采用台湾地区700多个地震台的P波初动极性资料确定了1991～2005年间该地区ML≥4.0级地震的震源机制解。由于涉及大量事件和台站,我们采用遗传算法非线性全局搜索震源机制解。该算法通过人工合成检验进行调整和验证。最终从4188个地震事件中得到了1635个高质量的地震震源机制解。大部分地震的震源机制解以逆冲为主,反映了板块碰撞造成的压缩应力场。正断层型事件发生在俯冲区的中等深度处,可能源于俯冲板块的弯曲。在欧亚板块内,北港基底高区(PeikangBasementHigh)附近和宜兰附近的板块碰撞较为复杂,也发现了走滑断层。我们的研究提供了研究发震结构和板块构造所需的震源机制数据库。该数据库也可被构造地震学家用来计算波形层析成像研究中的合成地震波形。
Based on the P-wave initial polarity data of more than 700 stations in Taiwan, the focal mechanism solution for the ML ≥ 4.0 earthquake in the area from 1991 to 2005 was determined. Due to the large number of events and stations involved, we use genetic algorithm nonlinear global search for focal mechanism solutions. The algorithm is adjusted and verified by synthetic test. Finally, 1635 high-quality focal mechanism solutions from 4,188 earthquakes were obtained. The focal mechanisms of most earthquakes are dominated by thrusting, which reflects the compressive stress field caused by plate collision. The normal fault type event occurs at the middle depth of the subduction zone, probably due to the bending of the subducting plate. In the Eurasian Plate, the plate collision near Peikang Basin Height near Peiyang and Ilan is more complicated and strike-slip faults are also found. Our study provides a database of focal mechanisms for studying seismogenic structures and plate tectonics. The database can also be used by seismologists to calculate synthetic seismic waveforms in wave tomography studies.