泸定M S6.8地震震前变形特征及鲜水河断裂南东段地震活动性  

Deformation Characteristics before the Luding M S6.8 Earthquake and Seismicity of the Southeast Section of the Xianshuihe Fault

作　　者：申星[1] 梁洪宝[1] 宋成科[1] SHEN Xing;LIANG Hongbao;SONG Chengke(The First Monitoring and Application Center,CEA,7 Naihuo Road,Tianjin 300180,China)

机构地区：[1]中国地震局第一监测中心,天津市300180

出　　处：《大地测量与地球动力学》2024年第1期69-74,共6页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(42174125);中国地震局震情跟踪定向工作任务(2023010416)。

摘　　要：针对鲜水河断裂带南东段的历史地震活动性和近10 a该断裂带上发生的中小震群展布特征,利用GNSS观测数据给出2022年泸定M S6.8地震震源区及周边区域的速度场、应变率场,识别此次地震震前的变形特征。GNSS速度场显示,鲜水河断裂带南东段走滑速率约为10 mm/a,区域整体运动为ES向,与断裂构造运动具有一致性;应变率场结果显示,发震断裂仍存在较强的剪切应变积累,汶川特大地震后随着应变能不断释放,龙门山断裂带的卸载作用间接影响鲜水河断裂带的南东段,该断裂长期处于应变积累高值的过渡区,现今仍具有较高的断层闭锁状态,该地区的地震活动趋势和地震危险性值得进一步关注和研究。Based on the historical seismicity of the southeast segment of the Xianshuihe fault zone and distribution of the earthquakes around the 2022 Luding M S6.8 earthquake in the past decade,using GNSS observation data,we give the velocity and strain rate field in the regional and surrounding areas,and identify the deformation characteristics before the earthquake.The GNSS velocity field shows that the strike slip rate of the southeast section of the Xianshuihe fault zone is about 10 mm/a,and the regional movement is in the ES direction,the same results with the regional structure.The strain rate field show that there is still a strong shear strain rate in the seismogenic fault.With the continuous release of strain energy after the Wenchuan earthquake,the unloading effect of the Longmenshan fault zone indirectly affects the southeast section of the Xianshuihe fault zone.The fault has been in a transition zone with high strain accumulation for a long time,the degree of fault blocking increased today.The trend of seismic activity and seismic risk in this area deserve further attention and research.

关 键 词：泸定6.8级地震 鲜水河断裂带 地震活动性 应变率场 

分 类 号：P313[天文地球—固体地球物理学] P315[天文地球—地球物理学]