基于重力数据的2022年青海门源M_(S)6.9及四川泸定M_(S)6.8地震预测  

Prediction of M_(S)6.9 Menyuan and M_(S)6.8 Luding earthquakes in 2022 based on gravity data

作　　者：赵云峰[1,2,3] 祝意青 隗寿春[1] 郑兵 刘芳[1] 杨雄[1] 毛经伦 孙和平 Yunfeng Zhao;Yiqing Zhu;Shouchun Wei;Bing Zheng;Fang Liu;Xiong Yang;Jinglun Mao;Heping Sun(The Second Monitoring and Application Center,China Earthquake Administraion,Xi’an 710054,China;Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430071,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Sichuan Seismological Bureau Crustal Deformation Observation Center,Yaan 625000,China)

机构地区：[1]中国地震局第二监测中心,西安710054 [2]中国科学院精密测量科学与技术创新研究院,武汉430071 [3]中国科学院大学地球与行星科学学院,北京100049 [4]四川省地震局地壳形变观测中心,雅安625000

出　　处：《科学通报》2023年第16期2116-2123,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(U1939205,41874092);陕西省自然科学基础研究计划(2021JQ-980)资助。

摘　　要：2022年,中国大陆西部地区接连发生多次6级强震.1月8日青海门源M_(S)6.9和9月5日四川泸定M_(S)6.8左旋走滑型地震均造成了显著的财产损失,后者更造成了百余人伤亡.地震前,依据中国地震局在两震中周边地区观测的重力数据获得了区域重力变化.结合此前多个典型地震前重力变化,该变化可能表明2021、2022年在青海门源、四川泸定及其附近地区会发生强震.两次地震实际震中与不同年度预测的地震危险区中心距离均不超过55 km.这两次地震前地表重力正、负变化均围绕震中相间出现,重力变化总体呈现四象限分布特征,且震中破裂区处于重力无变化区域.两次地震前重力变化与震源机制对比表明:四象限重力变化分布的正变化区对应于震源机制显示的压缩区、重力负变化区对应于震源机制显示的膨胀区.该发现有助于地震前兆理论的发展.Several strong earthquakes(with magnitudes≥6)occurred in western mainland of China in 2022.Two strike-slip earthquakes,an M_(S)6.9 in Menyuan county,Qinghai Province,on January 8,and an M_(S)6.8 in Luding county,Sichuan Province,on September 5,caused significant property damage,with the latter resulting in more than 100 casualties.For many years,the China Earthquake Administration has operated a gravity network near earthquake epicenters,with a number of relative and some absolute gravity stations serving as the main and auxiliary stations,respectively.In this study,the network was repeatedly monitored before the 2022 earthquakes;a large amount of relative gravity and a small amount of absolute gravity data were obtained,and changes in the regional gravity around the epicenter were determined.Changes in gravity fields are mainly reflected by relative gravity data,while absolute gravity data provide constraints.Based on the changes in gravity fields,we predicted the possibility of strong earthquakes of different magnitudes occurring in Menyuan county,Qinghai Province;Luding county,Sichuan Province;and their surrounding areas between 2021 and 2024.The distance between the epicenters of the two earthquakes recorded in 2022 and the center of the predicted earthquake risk zone in different years was<60 km,with distances being<10 km in 2021.Before the two earthquakes,positive and negative changes in surface gravity alternated around the epicenter and exhibited a four-quadrant distribution,one boundary axis of which coincided with seismogenic faults.The rupture zones of the earthquakes were located near the zero-value isolines of gravity changes.The maximum positive gravity change was>90×10–8 m s–2—Much greater than three times the observation error,while the minimum was approximately–40×10–8 m s–2.Both the amount of variation and the spatial extent of the positive changes were significantly greater than those of the negative ones.The spatial extent of gravity changes before both 2022 earthquakes was muc

关 键 词：门源M_(S) 6.9地震 泸定M_(S) 6.8地震 走滑型地震 地震预测 重力变化 

分 类 号：P315.7[天文地球—地震学]