山西地区的波速比(V_P/V_S)特征研究

A Study of Seismic Wave Velocity Ratio(V_P/V_S)of Shanxi Area

利用山西台网的数字地震观测资料,采用单震多台和达法、多震多台联合测定法,对山西北部、中部和南部地区波速比进行分析研究,结果表明:在2010年1月24日的河津万荣4.8级地震、4月4日的大同4.5级地震和6月5日阳曲4.6级地震前均存在波速比下降现象,其中前2次地震发生在波速比下降过程中,第3次地震则发生在波速比异常恢复阶段。之后山西中部和北部的波速比处于低值,尤其是山西北部的波速比低值持续,说明山西省北部是比较危险的区域。

On basis of digital seismic observation data in Shanxi province, using single earthquake multistation Wadati method and multi-earthquake and multi-station joint method, this paper calculated the velocity ratio of seismic waves （Vp/Vs） in northern, central and southern Shanxi area. Analytical investigation shows that： before Hejin-wanrong 4.8 earthquake on January 24, 2010, the Datong 4.5 earthquake on June 5, and Yangqu 4.6 earthquake, there is wave velocity ratio drop phenomenon. The top 2 earthquakes occurred in the process of wave velocity ratio decline, and the third earthquake occurred in the recovery phase. Then, wave velocity ratio in central and northern Shanxi keeps in low condition, especially the northern Shanxi area, which indicates that the northern Shanxi area is in risk of earthquake.