利用单台波形资料计算大柴旦6．3级地震余震震源机制

以2008年11月10日大柴旦Ms6．3级地震余震数字地震波观测资料为基础，运用矩张量反演方法，利用单台三分量波形资料计算余震的震源机制。收集整理大柴旦Ms6．3级地震公认的震源参数结果和青海区域地震台网数字地震波资料，以大柴旦Ms6．3级地震的震源参数作为约束，计算理论地震波来确定该区域的地壳速度模型。以此模型计算ML≥2．0级余震震源机制解。共收集160个余震资料，最后确定了85个余震震源机制解，其中最大震级为朋。4．7，最小震级为ML2.0。进行单台与多台联合矩张量反演结果对比，两种方法所确定的结果相差不大。实际计算表明，在观测资料信噪比较高的情况下，运用单台数字地震波观测资料可以较好地确定中小地震的震源机制。

USING SEISMIC DATA FROM A SINGLE-STATION TO CALCULATE THE FOCAL MECHANISMS OF THE AFTERSHOCKS OF THE Ms6.3 DACHAIDAN EARTHQUAKE IN NOV.10,2008

Based on the digital seismic data of the aftershocks of Dachaidan Ms6. 3 earthquake in Nov. 10, 2008, using the three-component seismic data from a single-station, we calculate the focal mechanisms of af- tershocks by the method of the moment tensors inversion. We collect the epicenter parameters published of Dachaidan Ms6.3 earthquake in Nov. 10, 2008 and the digital seismic data of the seismic network in Qinghai region. Through calculated theoretical seismic wave, we can get the velocity structure model of the research ar- ea in this paper by the epicenter parameters of Dachaidan Ms6.3 earthquake. Using this model, we obtain the focal mechanisms of the ME 92.0 aftershocks. We chosed the 160 aftershocks from the digital seismic data and got some results of 85 aftershocks at last, among which, the largest event is ML 4.7, the smallest magnitude is ML 2.0. Through contrast analysis, it almost is similar that we obtain the moment tensor inversion results from a single-station and the five stations. The calculated results show that the focal mechanisms of a small to mod- erate earthquakes can be gotten using the digital seismic data from a single-station.