【摘要】 收集整理了四川、云南、重庆3省市的数字地震波记录资料,反演该区域的中小地震震源机制解,并利用这些结果采用力轴张量法计算给出5个主要构造带(区)在汶川8.0级地震前后的平均应力场。对比汶川地震前后各主要构造带(区)应力场的状态发现,龙门山构造带南段、鲜水河构造带南段在汶川地震前后局部应力扰动明显,即震后平均应力场方位扰动值相对变化较大;鲜水河构造带南段、龙门山构造带南段和华蓥山构造带中段震后逆倾型地震明显减少。分析认为,这是巨大地震前后大范围地壳应力状态变化或调整的一种反映。更多还原

【Abstract】 After collecting digital seismic waveform records from Sichuan,Yunnan and Chongqing Seismic Telemetry Networks,we inverted focal mechanism solutions of moderate and small earthquakes in corresponding regions. On the basis of these results,the mean stress field of five main tectonic zones before and after the Wenchuan MS8. 0 earthquake has been worked out. Comparative study on each main tectonic zone before and after the Wenchuan MS8. 0 earthquake shows the complicated state of stress field. Local stress disturbance is obvious in south segments of Longmenshan tectonic zone and Xianshuihe tectonic zone before and after the Wenchuan MS8. 0 earthquake. That is larger relative changes of stress azimuth disturbance value occurring after the large earthquake. The proportion of reverse dip-slip earthquake decreased apparently in south segments of Xianshuihe tectonic zone and Longmenshan tectonic zone,and middle segment of Huayingshan tectonic zone after the large earthquake. We believe that it is a reflection of changes or adjustments of large-scale crustal stress state before and after the Wenchuan MS8. 0 earthquake.更多还原