Abstract: Based on the amplitude data of the direct waves recorded by the Shanxi Digital Seismic Network, we calculated the focal mechanism solutions of 281 small to moderate earthquakes from 2001 to 2012 in Shanxi region, by using the fast algorithm of the generalized transmission coefficient for the point source dislocation model in the layered media. According to the dominant distribution to get average tectonic stress field distribution of Shanxi region, we calculated the consistent parameters of focal mechanism between focal mechanism solutions and stress axis of the corresponding regional tectonic stress field, then analyzed the relationship between the spatial-temporal distribution of consistency parameters and the activity of moderate earthquake. The results show that the focal mechanisms before five M_L≥5.0 earthquakes since 2001 in Shanxi region all have consistent phenomena, and the epicenters were located near the low consistency value or in the transition zone of low and high values.

Key words: Consistency parameters of focal mechanism, Regional stress field, Shanxi region