VISCOELASTIC TRIGGERING BETWEEN LARGE EARTHQUAKES ALONG THE EAST KUNLUN FAULT SYSTEM
VISCOELASTIC TRIGGERING BETWEEN LARGE EARTHQUAKES ALONG THE EAST KUNLUN FAULT SYSTEM
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DOI：
10.1002/cjg2.432
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发表时间：
2003-11
期刊：
影响因子：
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通讯作者：
Zheng‐Kang Shen;Y. Wan;W. Gan;Yuehua Zeng;Qun Ren
中科院分区：
文献类型：
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作者：
Zheng‐Kang Shen;Y. Wan;W. Gan;Yuehua Zeng;Qun Ren
我们研究青藏高原北部东昆仑断裂系沿线的应力传递和大地震的触发。考虑了过去70年沿断裂带发生的5次7级地震：1937年华石峡谷7.5级地震、1963年都兰县MS7.1地震、1973年曼邑县MS7.3地震、1997年曼邑县MS7.5级地震和2001年可可西里MW7.8级地震。我们模拟了层状粘弹性介质中地震位错产生的应力演化过程，并计算了后续每次地震断层面上的库仑破坏应力变化。结果表明，科可西里地震断层面上的库仑破坏应力较前4次地震有所增加，且随着时间的推移，粘弹性松弛逐渐增强库仑破坏应力场。通过评估前4次大地震的同震破裂和粘弹性松弛产生的库仑破坏应力变化，我们发现在4次大地震中有3次，粘弹性松弛产生的库仑破坏应力变化比同震变形产生的库仑破坏应力变化显着得多。应力场模拟表明，可可西里地震发生后，东昆仑断裂带西大滩—东大滩段（可可西里段与都兰段之间）库仑破坏应力增加了0.05～0.10MPa，表明该地区地震潜力显着增加。
We study stress transfer and triggering of large earthquakes along the East Kunlun fault system, northern Tibetan Plateau. Five M 7 earthquakes occurred along the fault zone during the past 70 years are considered: the 1937 M7.5 Huashi Canyon, the 1963 MS7.1 Dulan, the 1973 MS7.3 Manyi, the 1997 MS7.5 Manyi, and the 2001 MW7.8 Kokoxili earthquakes. We simulate stress evolution process produced by seismic dislocation in layered viscoelastic media, and calculate Coulomb failure stress change on the fault plane of each subsequent earthquake. The result shows that the Coulomb failure stress on the fault plane of the Kokoxili earthquake was increased by the previous 4 earthquakes, and viscoelastic relaxation gradually enhanced the Coulomb failure stress field as time elapsed. By evaluating Coulomb failure stress change produced by coseismic rupture and viscoelastic relaxation of the 4 preceding large earthquakes, we find that Coulomb failure stress change produced by viscoelastic relaxation is much more significant than that produced by coseismic deformation in 3 of the 4 earthquakes. The stress field simulation indicates that after the Kokoxili earthquake Coulomb failure stress in the Xidatan-Dongdatan segment (between the Kokoxili and Dulan segments) of the East Kunlun fault is increased as much as 0.05 0.10MPa, implying significantly increased earthquake potential in this region.