河津地震序列的精定位研究

采用双差定位法,对2010年1月24日发生在山西河津与万荣交界的4.8级地震序列进行重新定位,结果显示,重新定位后,对于本次地震的发震构造,地震现场考察结果依据等震线图、余震分布特征,对震中区附近的主要活动断裂进行逐个排查分析,最终确定为NW向的西辛封断裂.

Study on the accurate location of Hejin earthquake sequence

Using double-difference location method, the M 4.0 earthquake sequence occurred at the joint area of Hejin and Wanrong, Shanxi on Jan 24, 2010 is relocated. The results show that, after relocation, the epicenter of main shock of Hejin M 4.8 （at Latitude 35.51°N,longitude 110.73°E,depth 2 km） is located the northern of Ermei platform, close to the macroepicenter observed by field investigation （at latitude 35.50°N,longitude 111.67°E）. The af- ter chocks are more concentrated, distributing mainly along NNW direction, few scattering along NEE direction. The residual root mean square deviation of locations after fine reloca- tion is 0.09 s. The estimate mean error （two times of standard deviation） is 0.24 km in EW direction, 0.19 km in NS direction, and 0.25 km in vertical direction. The causative fault determined finally, based on isoseismal line and the feature of after chock distribution obtained by the field observation, as well as the one by one analysis of main activity faults near epicentral area, is Xixinfeng fault with strike in NW direction