程佳^1,,
姚生海^2,,,
刘杰¹,
姚琪¹,
宫会玲³,
龙海云¹
1. 中国地震台网中心, 北京 100045
2. 青海省地震局, 西宁 810010
3. 广东省地震局, 广州 510070

基金项目: 国家自然科学基金（41404043）和中国地震局星火计划项目（XH16044和XH17045）联合资助


详细信息

作者简介: 程佳, 男, 1982年生, 副研究员, 主要从事地壳形变、地震构造、地震灾害预测模型等方面的研究工作.E-mail:chengjia@seis.ac.cn

通讯作者: 姚生海, 男, 1980年生, 高级工程师, 主要从事活动构造和古地震研究等方面的工作.E-mail:shenghaiyao@sina.com

中图分类号: P315

收稿日期:2017-09-16
修回日期:2018-03-15
上线日期:2018-05-05

Visoelastic Coulomb stress of historical earthquakes on the 2017 Jiuzhaigou earthquake and the subsequent influence on the seismic hazards of adjacent faults

CHENG Jia^1,,
YAO ShengHai^2,,,
LIU Jie¹,
YAO Qi¹,
Gong HuiLin³,
LONG HaiYun¹
1. China Earthquake Networks Center, Beijing 100045, China
2. Qinghai Earthquake Agency, Xining 810010, China
3. Guangdong Earthquake Agency, Guangzhou 510070, China


More Information

Corresponding author: YAO ShengHai,E-mail:shenghaiyao@sina.com

MSC: P315

--> Received Date: 16 September 2017
Revised Date: 15 March 2018
Available Online: 05 May 2018


摘要
摘要:首先对2017年九寨沟M_S7.0地震周边断裂活动和历史地震特征进行了阐述；然后利用黏弹性地壳模型，计算了1933年叠溪地震、1976年松潘震群和2008年汶川地震对2017年九寨沟地震的同震和震后库仑应力作用.该结果显示1933年叠溪地震对九寨沟地震具有延缓作用，而1976年松潘震群和2008年汶川地震对九寨沟地震的黏弹性库仑应力作用为正；随着下地壳和上地幔黏弹性物质的持续作用，前述几次地震总的黏弹性库仑应力在九寨沟地震破裂中心点处负的库仑应力逐渐减弱，而在破裂北段这些库仑应力逐渐转为正值，并促进了九寨沟地震的发生.本文也计算了九寨沟地震后对周边断层的库仑影响，并将此影响值转换为对断层能量积累的影响时间上，结果显示塔藏断裂带西段和中段在内的多条断裂带受到黏弹性库仑应力影响时间值超过10年.将库仑应力影响时间值加入到部分已知离逝时间的断层段上，也得到了这些断层段的未来30年特征地震发生概率.最终结果认为玛沁断裂带、玛曲断裂带、哈南—稻畦子断裂中段和西段等断层段的强震危险性需要重点关注.
关键词: 2017年九寨沟7.0级地震/
东昆仑断裂带尾端/
黏弹性库仑应力作用/
地震矩积累率/
强震危险性概率

Abstract:The M_S7.0 Jiuzhaigou earthquake in 2017 occurred in a complex tectonic region where the eastern Kunlun fault meets the Longmenshan fault. To study the interactions among the Jiuzhaigou earthquake and historical events in adjacent areas, we first present the slip features of the regional faults and historical records of major earthquakes. Then using the viscoelastic crustal model and historical rupture data, we calculate the coseismic and viscoelastic Coulomb stress changes (ΔCFS) on the seismogenic fault of the Jiuzhaigou earthquake from the M_S7.5 Diexi earthquake in 1933, the triplet events in 1976 with two M_S7.2 and one M_S6.7 earthquakes, and the M_S8.0 Wenchuan earthquake in 2008. The results show that the Diexi earthquake in 1933 had negative coseismic effect on the moment accumulation of the Jiuzhaigou earthquake in 2017, while the triplet events in 1976 and the Wenchuan earthquake in 2008 gave the positive coseismic effects. With the continuous viscoelastic effects induced by the lower crust and upper mantle, at the center of the seismogenic fault of the Jiuzhaigou earthquake, the negative ΔCFS has tapered gradually; while at the north end, the ΔCFS has changed from negative to positive, which might have promoted the occurrence of the Jiuzhaigou earthquake in 2017.
To analyze the seismic hazard of the nearby active faults after the Jiuzhaigou earthquake, we calculate the ΔCFS on these faults induced by all the earthquakes aforementioned, including the Jiuzhaigou earthquake. Then we transfer the calculated ΔCFS value to the influenced time of the characteristic earthquake energy accumulation for each fault segment based on the known slip rate. In our results, the ΔCFS values on several fault segments, including the western and the middle segments of the Tazang fault, are equivalent to more than 10 years of influence time on seismic moment accumulation. Adding this influence time to the elapsed time of the characteristic earthquakes on these segments, we obtain the conditional probabilities of the characteristic earthquakes in the next 30 years. Our results indicate that the seismic hazards on the following fault segments are high: the Maqên fault, Maqu fault, and the middle and western segments of the Hanan-Daoqizi fault.
Key words:M_S7.0 Jiuzhaigou earthquake in 2017/
Eastern Kunlun fault/
Viscoelstic Coulomb stress/
Seismic moment accumulation/
Probability of seismic hazard



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