Abstract: On the basis of the records of 6 stations in Hubei regional seismic network ， we obtained the focal mechanisms of the Ms 4.1 and Ms3.2 earthquakes in Zigui on Nov.22,2008 and Sep.27,2008, respectively with the Cut and Paste(CAP) method. The result shows that earthquakes have strike-slip and strike-slip fault mechanisms and the orientations of maximum compressional stresses are mainly in NE. It is certainly consistent with the orientation of the regional maximum compressional stresses .We deduce the earthquake is the reservoir induced earthquake by water permeation and dynamic changes load.The comparison shows that the focus mechanism of two events presented in this paper is consistent with that of small  moderate earthquakes determined by P-wave first-motion.

Key words: Zigui earthquake , focus mechanism solution , CAP method