Ductile gap between the Wenchuan and Lushan earthquakes revealed from the two-dimensional Pg seismic tomography.
Ductile gap between the Wenchuan and Lushan earthquakes revealed from the two-dimensional Pg seismic tomography.
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二维Pg地震层析揭示汶川、芦山地震间的延性间隙
DOI：
10.1038/srep06489
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发表时间：
2014-09-30
影响因子：
4.6
通讯作者：
Cui Z
中科院分区：
文献类型：
--
作者：
Pei S;Zhang H;Su J;Cui Z
获得了2013年4月20日中国芦山Ms7.0地震和2008年5月12日汶川Ms8.0地震震中周围上地壳的高分辨率二维Pg波速度模型。层析反演使用了芦山和汶川地震周围61个台站记录的6812次余震的47235个Pg波到时。在芦山地震附近的龙门山断裂前缘，存在强烈的速度差异，西部速度较高，东部速度较低。沿着龙门山断裂系，存在两个高速斑块，沿近西北 - 东南（NW - SE）方向呈钝角“X”形。它们分别对应地表的前寒武纪彭灌杂岩和宝兴杂岩，但分别有大约20公里的偏移。2008年汶川地震和2013年芦山地震的余震空区与较低速度相关。基于最大有效矩准则理论，这表明余震空区是薄弱的，在近NW - SE向挤压下，空区内的上地壳更可能发生韧性变形。因此，我们的结果表明在该空区内可能难以发生大地震。
A high-resolution two-dimensional Pg-wave velocity model is obtained for the upper crust around the epicenters of the April 20, 2013 Ms7.0 Lushan earthquake and the May 12, 2008 Ms8.0 Wenchuan earthquake, China. The tomographic inversion uses 47235 Pg arrival times from 6812 aftershocks recorded by 61 stations around the Lushan and Wenchuan earthquakes. Across the front Longmenshan fault near the Lushan earthquake, there exists a strong velocity contrast with higher velocities to the west and lower velocities to the east. Along the Longmenshan fault system, there exist two high velocity patches showing an “X” shape with an obtuse angle along the near northwest-southeast (NW-SE) direction. They correspond to the Precambrian Pengguan and Baoxing complexes on the surface but with a ~20 km shift, respectively. The aftershock gap of the 2008 Wenchuan and the 2013 Lushan earthquakes is associated with lower velocities. Based on the theory of maximum effective moment criterion, this suggests that the aftershock gap is weak and the ductile deformation is more likely to occur in the upper crust within the gap under the near NW-SE compression. Therefore our results suggest that the large earthquake may be hard to happen within the gap.
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影响因子：
1.4
作者：
Liu Jie;Yi Gui-Xi;Du Fang
通讯作者：
Du Fang
影响因子：
3
作者：
Pei, Shunping;Chen, Yongshun John
通讯作者：
Chen, Yongshun John
影响因子：
4.2
作者：
Densmore, Alexander L.;Ellis, Michael A.;Richardson, Nicholas
通讯作者：
Richardson, Nicholas
影响因子：
3
作者：
Pei, Shunping;Zhao, Junmeng;Sun, Youshun
通讯作者：
Sun, Youshun
2013年4月20日四川芦山地震破裂过程初步结果
影响因子：
1.4
作者：
Wang Wei-Min;Hao Jin-Lai;Yao Zhen-Xing
通讯作者：
Yao Zhen-Xing