| 基于库仑应力变化分析巴颜喀拉地块东端的强震相互关系 |
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| 引用本文： | 徐晶,邵志刚,刘静,季灵运.基于库仑应力变化分析巴颜喀拉地块东端的强震相互关系[J].地球物理学报,2017,60(10):4056-4068. |
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| 作者姓名： | 徐晶 邵志刚 刘静 季灵运 |
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| 作者单位： | 1. 中国地震局地质研究所, 北京 100029;
2. 中国地震局第二监测中心, 西安 710054;
3. 中国地震局地震预测研究所, 北京 100036 |
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| 基金项目： | 中国地震局实验场项目（20150115）和国家自然科学基金项目（41604015）共同资助. |
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| 摘 要： | 本研究基于分层黏弹介质模型,考虑同震位错效应和震后黏滞松弛效应,分析巴颜喀拉地块东端1976年松潘地震序列、2008年汶川8.0级地震、2013年芦山7.0级地震和2017年九寨沟7.0级地震等多次大地震的可能存在的触发关系,计算大地震引起的周边各主要断裂的库仑应力变化.结果显示,1976年松潘地震序列各次地震间关系密切,存在明显的相继触发作用;综合考虑同震和震后效应,汶川8.0级地震对同属于龙门山断裂带的芦山7.0级地震有触发作用,且震后效应影响不可忽略;1976年地震序列,特别是1976年8月16日7.2级地震促进了2017年8月8日九寨沟7.0级地震的发生;汶川地震对九寨沟地震的影响研究中,采用不同的汶川地震同震位错模型,计算结果有差异.综合考虑多次大地震对周边断裂带的影响,龙门山断裂带南段、鲜水河断裂带中南段、平武—青川断裂北段、灌县—安县断裂北段、文县断裂的累积库仑应力增加显著,巴颜喀拉地块东端的东昆仑断裂带东段、迭部—白龙江断裂带西段以及金沙江断裂带库仑应力亦有所增加.综合考虑各重要断裂带已有的大地震危险性分析结果和库仑应力变化计算结果,龙门山断裂带南段、鲜水河断裂带中南段、东昆仑断裂带玛沁—玛曲段和金沙江断裂带的发震紧迫性有所增强,需引起关注.
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| 关 键 词： | 巴颜喀拉地块东端 震后黏滞松弛 地震触发 库仑应力变化 强震危险性 |
| 收稿时间： | 2017-08-30 |
Analysis of interaction between great earthquakes in the eastern Bayan Har block based on changes of Coulomb stress |
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| XU Jing,SHAO Zhi-Gang,LIU Jing,JI Ling-Yun.Analysis of interaction between great earthquakes in the eastern Bayan Har block based on changes of Coulomb stress[J].Chinese Journal of Geophysics,2017,60(10):4056-4068. |
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| Authors: | XU Jing SHAO Zhi-Gang LIU Jing JI Ling-Yun |
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| Institution: | 1. Institute of Geology, China Earthquake Administration, Beijing 100029, China;
2. Second Monitoring and Application Center, China Earthquake Administration, Xi'an 710054, China;
3. Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China |
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| Abstract: | Using a more realistic model of multi-layered viscoelastic media, we examine the effects of the coseismic dislocation and the postseismic viscoelastic relaxation. Then we analyze the interaction between several great earthquakes which occurred in the eastern Bayan Har block, including the 1976 Songpan earthquake sequence, 2008 Wenchuan MS8.0 earthquake, 2013 Lushan MS7.0 earthquake, and the 2017 Jiuzhaigou MS7.0 earthquake. Furthermore, based on the calculation of the Coulomb stress changes caused by these events on the fault planes, we assess the seismic hazard of the major fault in the study area.
The results show that there is a correlation between the events of the Songpan earthquake sequence in 1976, the first event may trigger the second one, and the two previous events may trigger the third event. Considering the coseismic and the postseismic effects, the 2008 Wenchuan MS8.0 earthquake might have triggered the 2013 Lushan MS7.0 earthquake, both ruptured the Longmenshan fault zone. The 1976 Songpan earthquake sequence, especially the August 16, 1976 event of magnitude of MS7.2, had contributed to the occurrence of the August 8, 2017 Jiuzhaigou MS7.0 earthquake. When studying the influence of the 2008 Wenchuan earthquake on the 2017 Jiuzhaigou event, we employ different coseismic dislocation models and obtain different results.
The resultant Coulomb stress changes on the major fault segments associated with all of the previous events show that, considering the comprehensive influence of all the great events on the surrounding fault zones, the cumulative Coulomb stress increases significantly in the southern segment of the Longmenshan fault zone, the south-central segment of the Xianshuihe fault zone, the northern segment of the Pingwu-Qingchuan fault, the northern segment of the Guanxian-Anxian fault, and the Wenxian fault. And the cumulative Coulomb stress also increased in the eastern segment of the Dongkunlun fault, the western segment of the Diebu-Bailongjiang in the eastern Bayan Har block and the Jinshajiang fault. Comprehensive considering the results of the Coulomb failure stress changes and the existing research results about the great earthquake hazard of the major faults, we should focus more attention on the earthquake hazard in the southern segment of the Longmenshan fault zone, the south-central segment of the Xianshuihe fault zone, the Maqin-Maqu segment of the Dongkunlun fault zone and the Jinshajiang fault. |
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| Keywords: | Eastern Bayan Har block Postseismic viscoelastic relaxation Earthquake triggering Coulomb stress change Seismic hazard |
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