新疆北天山非弹性衰减、场地响应及其震源参数研究

本文利用新疆北天山22个数字地震台的地震波形资料，首先采用Atkinson方法得到了北天山Q值随频率f的关系式为Q(f)=465.2f^0.53; 其次采用Moya方法反演得到了22个台站的场地响应，结果显示，绝大多数台站的场地响应在1附近，其中5个台站的场地响应表现出不同程度的放大效应，可能与台基岩性和仪器工作状态有关; 最后用ω平方震源模型计算了161次地震的震源参数，结果表明，在单对数坐标下，161次地震震级(M_S)与地震矩的对数、震源破裂半径、矩震级呈正相关关系、与拐角频率呈负相关关系、与应力降并无明显的依存关系，进而利用震源参数中的应力降时序图，分析了研究区内2次6级地震前后应力降随时间的变化特征: 表现为震前出现高应力异常，震后趋于低值的变化过程。

Non-elastic Attenuation,Site Response and Source Parameters in the Northern Tianshan Mountain,Xinjiang of China

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.