Crustal deformation across the Longmen Shan fault zone from finite element simulation of seismic cycles

被引:4
作者
Yin Li [1 ]
Luo Gang [1 ]
机构
[1] Chinese Acad Sci, Univ Chinese Acad Sci, Key Lab Computat Geodynam, Beijing 100049, Peoples R China
来源
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION | 2018年 / 61卷 / 04期
关键词
Longmen Shan fault zone; Seismic cycle; Short-term and long-term deformation; Visco-elastic-plastic finite element modeling; SAN-ANDREAS FAULT; WAVE VELOCITY STRUCTURE; 7.9 WENCHUAN EARTHQUAKE; TIBETAN PLATEAU; EASTERN MARGIN; UPPER-MANTLE; SURFACE DEFORMATION; SOUTHERN CALIFORNIA; SLIP RATES; MODEL;
D O I
10.6038/cjg2018L0248
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
The present-day crustal deformation data show the shortening rate is less than 3 mm.a(-1) across the Longmen Shan fault zone. Such a small shortening rate is a sharp contrast to the long-term orogeny with topographic relief of about 4. 5 km. To address this issue, this work constructs a series of 2-D plane strain visco-elastic-plastic finite element models to explore the relationship between short-term and long-term deformation. We simulate the surface displacement of different stages (inter-seismic, co-seismic and post-seismic) in one seismic cycle, and the total displacement of multiple seismic cycles. The results show that permanent deformation leading to orogeny is generated after a seismic cycle. The rheological contrasts in the lithosphere and fault geometry have a significant effect on surface displacement distribution. After multiple seismic cycles, the eastern Tibetan plateau experiences overall uplift and shortening, while the Sichuan basin remains relatively stable. The shortening of the entire region is mainly accommodated by fault slip along the Longmen Shan fold-and-thrust zone, resulting in differential uplift between the eastern Tibetan plateau and the western Sichuan basin. Our model links the short-term deformation of multiple seismic cycles with long-term geologic orogeny, which helps the understanding of the uplift mechanism of the eastern Tibetan plateau.
引用
收藏
页码:1238 / 1257
页数:20
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