用PTD方法测定巴林左旗5.9级地震震源深度

Locating the focal depth of Balinzuoqi M_S5.9 earthquake using the PTD earthquake location algorithm

震源深度是描述震源的最基本参数之一,给出了地震发生在地球内部的具体位置,对了解地震孕育和发生的物理化学条件,以及地震能量集结、释放的活动构造背景都有重要的意义。根据PTD方法,对2003年8月16日发生的内蒙古自治区巴林左旗5.9级地震的震源深度进行了测定,测定震源深度为20km,与东北地震构造区地震平均深度11±5km相比偏深。文中进一步分析讨论了对测定结果产生误差的各种因素,给出了减小误差的应对措施;在此基础上结合相关研究成果对地震区周围的地壳P波速度结构进行了探讨,给出了具体的P波二层均匀速度结构。

Focal depth is one of the most basic seismological parameters, showing where the earthquake occurred in the earth, which will be of great significance to investigate the physical and chemical condition of seismic generation and occurrence, the tectonic background for concentration and release of seismic energy. In this paper the focal depth of the Balinzuiqi M_S5.9 earthquake occurred on Aug. 16, 2003 was determined using the PTD earthquake location algorithm. The result is 20 km, which is deeper than the average focal depth (11±5) km in Northeast China block. Then this paper analyzes the result error, and gives solution. At last, it discusses the velocity structure of P wave of the crust in the earthquake region combined with correlative results, and two layers homogeneous velocity structure of P wave in the earthquake region is given.