CAJ | 학술논문

基于青藏高原及邻区的三维粘弹性有限元模型,讨论2008年于田 MS7.3级地震与2014年于田MS7.3级地震之间的关系,并研究2014年于田MS7.3级地震的发生造成周围断层的库仑破裂应力变化。初步结果表明：1)2008年于田MS7.3级地震在2014年于田MS7.3级地震震中滑动方向上产生的库仑破裂应力变化高于地震触发的阈值0.01 MPa,存在明显的触发作用。在视摩擦系数分别取0.4和0.6时,震源区同震库仑破裂应力变化为0.0167 MPa和0.0170 MPa；而考虑粘弹性松弛作用时产生的库仑应力增加量分别为0.0187 MPa和0.0194 MPa。结合断裂带构造应力年累计速率的结果,2008年于田地震的发生造成2014年于田地震提前21.4~24.9 a；2)在较短的时间尺度内,对于距离相近的两次地震之间,同震产生的应力变化远大于粘弹性松弛效应产生的变化；3)2014年于田MS7.3级地震的发生造成阿尔金断裂中北段、玛尼—玉树断裂中段、东昆仑断裂西段、柴达木北缘断裂东段、西秦岭北缘断裂西段等不同程度的加载效应,地震危险性有所增强。其中阿尔金断裂中段库仑应力增加最为明显,最大达2.8×10–3 MPa；玛尼—玉树断裂中段次之,应力增加量最大达5.6×10–4 MPa；东昆仑断裂西段应力增加量最大达4.75×10–4 MPa。而玛尼—玉树断裂西段库仑破裂应力最大卸载量达3.6×10–3 MPa。
기우청장고원급린구적삼유점탄성유한원모형,토론2008년우전 MS7.3급지진여2014년우전MS7.3급지진지간적관계,병연구2014년우전MS7.3급지진적발생조성주위단층적고륜파렬응력변화。초보결과표명：1)2008년우전MS7.3급지진재2014년우전MS7.3급지진진중활동방향상산생적고륜파렬응력변화고우지진촉발적역치0.01 MPa,존재명현적촉발작용。재시마찰계수분별취0.4화0.6시,진원구동진고륜파렬응력변화위0.0167 MPa화0.0170 MPa；이고필점탄성송이작용시산생적고륜응력증가량분별위0.0187 MPa화0.0194 MPa。결합단렬대구조응력년루계속솔적결과,2008년우전지진적발생조성2014년우전지진제전21.4~24.9 a；2)재교단적시간척도내,대우거리상근적량차지진지간,동진산생적응력변화원대우점탄성송이효응산생적변화；3)2014년우전MS7.3급지진적발생조성아이금단렬중북단、마니—옥수단렬중단、동곤륜단렬서단、시체목북연단렬동단、서진령북연단렬서단등불동정도적가재효응,지진위험성유소증강。기중아이금단렬중단고륜응력증가최위명현,최대체2.8×10–3 MPa；마니—옥수단렬중단차지,응력증가량최대체5.6×10–4 MPa；동곤륜단렬서단응력증가량최대체4.75×10–4 MPa。이마니—옥수단렬서단고륜파렬응력최대사재량체3.6×10–3 MPa。
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 YutianMS7.3 earthquake and the antecedent YutianMS7.3 earthquake in 2008. Then, the coseismic Coulomb failure stress change of the surrounding faults caused by the YutianMS 7.3 earthquake in 2014 was analyzed. Some preliminary conclusions have been reached: 1) the Coulomb failure stress change caused by the YutianMS7.3 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 4.75×10-4MPa 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.