甘肃地区震源参数的相关性研究

Study on source parameters and its similar relationship of earthquakes occurred in Gansu region

通过对甘肃数字地震台网2008年1月—2009年6月记录的M_L 2.0—M_L 6.0中小地震,S波观测谱中噪音、仪器、路径、场地等影响的逐一消除,利用遗传算法反演得到甘肃地区273条地震的震源谱,进而根据Brune的圆盘震源模型,计算地震矩、应力降、拐角频率、震源半径等震源参数,并研究甘肃地区震源参数的特征及相似关系。结果表明:这些地震的标量地震矩M_0与M_L震级线性相关较好,关系为lgM_0=0.977M_L+10.336;拐角频率在1.3—15 H_z;应力降介于0.1—15 MPa,优势分布于1—10 MPa,且与M_L有一定的依赖关系。

Base on the regional data recorded by Gansu Digital Seismic Network, we first corrected the observational seismic S waveform data by removing the noise, instrument, propagation and site effects. Then, we obtained source spectra for 273 earthquakes with magnitude ML 2. 0 to ML 6. 0 and determined the source parameters including seismic moment, stress drop, corner frequency, and source dimension etc. , based on the Brune model. Finally, 273 source parameters are gained. We study on source parameters and its similar relationship of these earthquakes. The result shows that the seismic moment and local magnitude remains a high correlation, which is lgM0 =0. 977 ML q-10. 336; The corner frequency of 273 events range between 1.3 to 15 Hz~ The stress drops range between 1.3 to 15 MPa, dominantly distribute between 1 and 10 MPa and the stress drop seems independent of local magnitude.