| 两次于田MS7.3地震间应力触发作用及2014年于田地震的发生对周缘断层的影响 |
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| 关键词:Yutian earthquake Altun fault Coulomb failure stress viscoelastic relaxation numerical simulation |
| 基金项目:国家科技支撑计划项目(编号: 2012BAK19B03-6);中央公益性科研院所基本科研业务专项(编号: ZDJ2014-03; ZDJ2012-09);国家自然科学基金项目(编号: 41104058) |
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| Stress Triggering between the Two Yutian MS7.3 Earthquakes and the Influence of the Yutian Earthquake in 2014 on the Surrounding Faults |
| In this paper, the three-dimensional finite element model for the Tibetan Plateau and its adjacent region was employed to explore the possible relationship between the 2014 Yutian MS7.3 earthquake and the antecedent Yutian MS7.3 earthquake in 2008. Then, the coseismic Coulomb failure stress change of the surrounding faults caused by the Yutian MS 7.3 earthquake in 2014 was analyzed. Some preliminary conclusions have been reached: 1) the Coulomb failure stress change caused by the Yutian MS7.3 earthquake in 2008, which was projected in the slip direction of the 2014 Yutian earthquake epicenter, exceeded the earthquake triggering threshold, which demonstrates the apparent triggering effect. Specifically, the coseismic Coulomb failure stress changes were 0.0167 MPa and 0.0170 MPa when we assumed 0.4 and 0.6 as the apparent friction coefficients; meanwhile, the Coulomb failure stress changes incorporating the coseismic and viscoelastic relaxation effects were 0.0187 MPa and 0.0194 MPa respectively. The later 2014 Yutian earthquake advanced the antecedent Yutian earthquake in 2008 by 21.4~25.9 a, as shown by the tectonic stressing rate; 2) in a relatively short time scale, the stress change induced by the coseismic effect is greater than the viscoelastic effect for the two successive earthquakes; 3) the Coulomb failure stresses increased along the mid-north segment of Altun fault, middle segment of Mani-Yushu fault, western segment of Eastern Kulun fault, eastern segment of northern Qaidam fault and western segment of northern margin of West Qinling, suggesting the increasing seismic risk. Among these structures, the Coulomb failure stress increased by 2.8×10-3 MPa in the middle segment of Altun fault at the maximum, 5.6×10-4 MPa in the middle segment of Mani-Yushu fault, and 4.75×10-4 MPa in the western segment of Eastern Kunlun fault. In addition, the Coulomb failure stress decreased by 3.6×10-3 MPa in the western segment of Mani-Yushu fault. |
| LI Yu-jiang,CHEN Lian-wang,YANG Shu-xin,LIU Shao-feng,YANG Xing-yue.2015.Stress Triggering between the Two Yutian MS7.3 Earthquakes and the Influence of the Yutian Earthquake in 2014 on the Surrounding Faults[J].Acta Geoscientica Sinica,36(1):94-102. |
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