Abstract: The focal mechanism solution of 15 earthquakes in Fujian Shuikou reservoir area is calculated. It is found that the hypocenter parameters during the early impounding are different and the hypocenter parameters during the late impounding are basically consistent. Besides, this paper analyzed the orientation and functional type of tectonic principal stresses and the seismic faults' slip features during the early and late impounding. Although both kinds of earthquakes are reservoir-induced, the earthquakes in the late impounding evidently have the tectonic feature. These results are of certain significance for analysis on other reservoir-induced earthquakes.

Key words: Focal mechanism, Shuikou reservoir, Reservoir-induced earthquake, Tectonic earthquake