Abstract: Based on seismic wave data recorded by 22 digital seismic stations in the northern Tianshan mountain, Xinjiang of China. Firstly, the relation of Q values of non-elastici attenuation in the northern Tianshan with frequency f is estimated as Q(f)=465. 2f^{0. 53} using the method proposed by Atkinson. Then, site responses of the stations were investigated with the Moya method. The results show that the most site response is about 1. 0, and 5 stations showed different amplifications. Finally, We use the omega-squared model to obtain source parameters of 161 earthquakes. The results show that, at the single algorithm coordinate, the relation is positive among seismic magnitude, seismic moment and hypocenter scale, but opposite between seismic magnitude and corner frequency, there is not distinct relation between seismic magnitude and stress drop. And then, using the stress drop sequence diagram of source parameters, we analyzed the change characteristics of stress drop before and after two magnitude 6 earthquakes, which was the change process of the high stress before earthquakes and tending to low value after earthquakes.

Key words: Non-elasticity attenuation, Quality factor, Site response, Source parameters, Northern Tianshan of Xinjiang