基于重复地震估算石屏—建水断裂带深部滑动速率  

Deep slip rates along the Shiping-Jianshui fault zone estimated from repeating earthquakes

作　　者：王光明 姜金钟[1,2] 郑定昌 赵小艳[1] 彭关灵 陈棋福[3,4] WANG GuangMing;JIANG JinZhong;ZHENG DingChang;ZHAO XiaoYan;PENG GuanLing;CHEN QiFu(Yunnan Earthquake Agency,Kunming 650224,China;Kunming Institute of Earthquake Prediction,China Earthquake Administration,Kunming 650201,China;Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]云南省地震局,昆明650224 [2]中国地震局昆明地震预报研究所,昆明650201 [3]中国科学院地质与地球物理研究所,中国科学院地球与行星物理重点实验室,北京100029 [4]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地球物理学报》2025年第2期547-563,共17页Chinese Journal of Geophysics

基　　金：地震科技星火计划项目(XH24037YB,XH20054Y);云南省重点研发项目(202203AC100003);国家自然科学基金(91958209);国家自然科学基金青年项目(42104060)共同资助.

摘　　要：2021年以来川滇菱形块体连续发生的中强地震预示该块体可能进入强震活跃阶段,位于块体东南缘的石屏—建水断裂带的强震危险性值得关注.基于重复地震估算得到断层深部滑动速率及其随时间的演化特征,对未来强震发生的地点和时间具有一定的指示意义.本研究利用云南地震台网2009—2021年的波形记录和震相到时信息,通过波形互相关技术在石屏—建水断裂带及周边地区识别出12组包含4个及以上地震的重复地震序列.基于重复地震估算出石屏—建水断裂带5.0~16.8 km深度范围内的滑动速率为1.9~11.4 mm·a^(-1),平均值为5.7 mm·a^(-1),中值为5.25 mm·a^(-1).石屏—建水断裂带不同段落的滑动速率差异较大:断裂带西段深部滑动速率均值(4.2 mm·a^(-1))与浅层滑动速率(2.8~5.3mm·a^(-1))基本一致;而东段深部滑动速率均值(9.4mm·a^(-1))约为浅层滑动速率的2倍.根据强震孕育过程的变形模式分析,石屏—建水断裂带西段目前可能正处于强震孕育的震间阶段,而石屏—建水断裂带东段可能处于强震孕育的震前阶段,但可能还未进入亚失稳阶段;石屏县城和建水县城之间的区域可能是未来强震发生的地点.结合地质构造、速度结构等方面分析,认为石屏—建水断裂带东段强震危险性较高,建议对该区域进行强化跟踪研究.The continuous occurrence of strong earthquakes in the Sichuan-Yunnan rhombic block indicates that the block may enter the active stage of strong earthquakes.Thus the earthquake risk of the Shiping-Jianshui fault zone(SJFZ)located in the southeastern margin of the block deserves attention.Deep slip rates along the fault and its evolution characteristics with time,which has certain indicative significance for the location and occurrence time of future strong earthquakes,are estimated from repeating earthquake sequences(RESs).In this study,we use the waveform data recorded by the Yunnan Seismic Network between 2009 and 2021 to search for RESs along the SJFZ.Using waveform cross-correlation technique,12 RESs which containing 4 or more earthquakes are identified in the study area.The fault slip rate computed from the RESs varies from 1.9 to 11.4 mm·a^(-1) at depth 5.0~16.8 km,with an average value of 5.7 mm·a^(-1) and a median value of 5.25 mm·a^(-1).The slip rates along different sections of the SJFZ are quite different.The average deep slip rate(4.2 mm·a^(-1))along the western segment of the SJFZ is basically consistent with the shallow slip rate(2.8~5.3 mm·a^(-1))inferred from surface Global Positioning System(GPS)and geological data.While the average deep slip rate(9.4 mm·a^(-1))along the eastern segment of the SJFZ is approximately twice as large as the shallow slip rate.Based on the deformation pattern of strong earthquake cycles,the western segment of the SJFZ may be in the interseismic stage,while the eastern segment of the SJFZ may be in the pre-earthquake stage,but may not have entered the meta-instability stage.The area between Shiping County and Jianshui County may be the epicenter of the strong earthquakes in the future.The analysis of the RESs,geological structure,and velocity structure of the study area suggests that the eastern segment of the SJFZ has a high risk of strong earthquakes in the future,and we recommend enhancing the capacity of earthquake monitoring and research in this area.

关 键 词：重复地震 断层滑动速率 石屏—建水断裂带 地震危险性 

分 类 号：P315[天文地球—地震学]