2014年2月12日于田7.3级地震对青藏东北缘地震活动的影响分析

Impact of the February 12,2014 Yutian M_S7.3 Earthquake on Seismicity of the Northeastern Edge of Tibet

首先,利用"中国地壳运动观测网络"和"中国构造环境观测网络"截至2013年的GPS区域站观测资料,结合地质构造,简要分析了2014年2月12日新疆于田7.3级地震前大区域地壳水平运动变形背景;接着,对青藏块体东北缘地区GPS和精密水准两种不同类型资料反映的地壳运动变形与应变积累状态进行了对比分析研究;最后,结合地震活动动力环境,研究和探讨了于田7.3级地震的发生对青藏块体东北缘地震活动的可能影响。我们认为,此次于田7.3级地震发生在近年来中国西部边邻强构造活动环境和内陆地壳强烈差异运动显著的背景下,同时也是青藏块体及其边缘构造应力场较强的时段;于田7.3级地震左旋走滑错动和应力传递,可能会加速青藏块体东北缘具有高应变积累的构造断裂部位(尤其是祁连山构造带、西秦岭以南的甘青川交界)破裂释放。

Using the GPS velocity field from the campaign GPS measurement implemented by CMONC （China Crustal Movement Observation） and TEONC （China Tectonic Environment Observation Networks） up to 2013,we first analyzed the background of regional crustal horizontal movement and deformation before Yutian Ms7.3 earthquake in Xinjiang,which occurred on 12 February 2014.Then,we analyzed the crustal movement deformation and state of strain accumulation at the northeastern edge of Tibet,by comparing to the vertical movement from leveling measurement.Finally,we investigated the earthquake activity at the northeastern edge of Tibet,which may be affected by Yutian Ms7.3 earthquake.The result indicated that,Yutian Ms7.3 earthquake occurred in the background of strong tectonic movement at the margins of western area and inland crustal differential movement,and also happened in the time of strong tectonic stress field in Tibet and its margins.The sinistral strike slip and stress transfer of the Yutian Ms7.3 earthquake may accelerate the rupture of fault positions with high strain accumulation at the northeastern edge of Tibet,specially in Qilianshan fracture zone,the junction of Gansu,Qinghai and Sichuan Province at the south of western Qinling）.