Comparative study on crustal earthquakes along active faults

宁夏回族自治区位于西藏地块、华北地块和鄂尔多斯地块的结合带。1997年在5个新建台站进行了两次GPS观测，观测结果表明，由于印度板块与欧亚板块的碰撞，西藏地块以每年约3厘米的速度向东北方向移动。1997年，东北大学在宁夏回族自治区地震局安装了一套基于PC的地震仪数据采集系统，其使得能够精确地定位震源并记录数字波形数据。波形的初步研究表明，存在一些独特的后期阶段，这些阶段被认为是地壳中的反射体。波形数据质量高，有可能用于今后的震源过程研究、地震层析成像等。

Ningxia Hui Autonomous Region is located in the junction zone of Tibet block, North China block and Ordos block. Two GPS campaigns were operated at five newly constructed stations in 1997, which have revealed that Tibet block was moved toward northeast with a rate of about 3cm per year due to the collision between the Indian and Eurasian plates.In 1997, a PC-based data acquisition system for seismographs was installed at the Seismological Bureau of Ningxia Hui Autonomous Region, Yinchuan, China by Tohoku University, which has enabled to locate hypocenters accurately and to record digital wave form data. Preliminaly investigations of waveforms show the existence of some distinctive later phases, which are thought to be reflectors in the crust. The quality of waveform data is so high that it may be possible to be used for future researches of source process of earthquakes, seismic tomography, and so on.