汶川MS8.0地震逆冲滑动量沿断层深度的分布有明显的特点,可以分解成三个破裂的滑动量叠加：深度18 km附近的底部破裂滑动、深度11 km附近的中部破裂滑动和两个局部破裂以外的主体滑动.扣除局部破裂滑动量后,沿断层走向从映秀到南坝近200 km范围内,逆冲滑动量沿断层深度的分布形态是一致的.基于滑动反演几何模型的有限元模拟显示,汶川地震逆冲滑动分布的整体性特征可能源自于断层浅部构造及巴彦喀拉块体SE向挤压强度沿断层走向上的一致性.
The Wenchuan Ms8.0 earthquake occurred on the Longmenshan fault zone,which is a convergent zone separating the Sichuan basin from the Bayan Har block. In this paper,we analyze the latest slip model inverted from geodetic data. We find that the thrust slip distributions along the fault depth in different segments of the Wenchuan MsS. 0 earthquake have common character- istics, although there are apparent complexities and differences in the Yingxiu segment, the Hongkou segment and the Beichuan segment. We decompose the thrust slip into three segments. The total amount of slip in the three segments can be decomposed into three partial slides. The first partial slide is a bottom slide distributed at a starting depth of around 17 or 18 kin,with the depth range of the slide being about 2 km. The second partial slide is an intermediate slide distrib- uted at a starting depth of around 11 kin,with the depth range of the slide being about 10 km. The third slide is the remaining slide after removing the previous two partial slides from the total slip amount. The first partial slide and the second partial slide may be caused by some local rupture energy,and probably have little to do with the macroscopic mechanical environment. Thus, we take the third slide as the typical thrust slip of the three segments to compare with the other seg- ments. After the above decompositions, the thrust-slip distributions in the Yingxiu segment, the Hongkou segment and the Beiehuan segment seem to show a similar shape with the other seg- ments. That means the thrust-slip distributions along the fault depth in the Wenchuan Ms8. 0 earthquake exhibit almost the same shape and follow the strike of the fault within the 200 km range from Yingxiu to Nanba,which may lead to the consistency. We construct a plane-strain nu- merical model using a finite-element method to examine the potential strike-slip scenarios. Our fi- nite-element model takes the same geometry as used in the inversion of the slip model, with the exception of using a spline to imita
Northwestern Seismological Journal
Wenchuan Ms8.0 earthquake
the finite-element method