Abstract: The focal mechanisms of moderate-small earthquakes are calculated tentatively using digital seismic wave data in some provincial digital seismic networks based on the program of focal mechanism determinations combing the first motion of P, SV and SH waves with their amplitude ratio, which is recently developed by Snoke. Some results are compared with the results obtained by P first motion data. It shows that the method is feasible, and it provides a new possibility using digital seismic data in earthquake prediction.

Key words: Focal mechanism, First motion, Amplitude ratio