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DOI	10.1093/gji/ggac153
	Three-dimensional finite element modelling on strain localization around the Mabian earthquake swarm, Sichuan Province
	Zhu, Xiaojie; He, Jiankun; Wang, Xinguo; Xiao, Jie
通讯作者	He, JK (通讯作者)
发表日期	2022
ISSN	0956-540X
EISSN	1365-246X
起始页码	1852
结束页码	1863
卷号	230 期号:3
英文摘要	The Mabian fault zone, distanced similar to 200 km to the east of the Xianshuihe-Xiaojiang fault system, is located in the western vicinity of the relatively stable South China Block. Since 1917, about 54 M > 4.7 earthquakes, including the 1974 Ms = 7.1 Mabian event have occurred around this fault zone, suggesting that significant strain is localized within the Mabian fault zone. Here, we built a 3-D finite element model to investigate the main parameters that possibly control strain localization around the Mabian fault zone averaged over the active deformation timescale. In the model, the Xianshuihe-Xiaojiang fault system is specified as a discontinuous contact interface for its motion governed by a Coulomb-friction law, and the crustal rheology is simplified as a frictional upper crust underlain by a viscoelastic lower crust. In addition, global positioning system (GPS) data are used to mimic the horizontal tectonic loading, and the model base is supported by a hydrostatic pressure. Numerical results show that with the weak fault strength and the low viscosity contrast between the Tibetan plateau and the South China Block, strain rates from motion of the southeastern Tibetan plateau could be propagated across the Xianshuihe-Xiaojiang fault system more widely within the Mabian fault zone. Constrained by the estimates on slip rates of the faults and on rheological structures of the crust, our optimal model predicts the effective friction coefficient of the Xianshuihe-Xiaojiang fault of 0.05-0.1. Under this condition, relative motion across the Xianshuihe-Xiaojiang fault system is largely partitioned by the geometric bend near the central portion of the fault system, resulting in a relatively high strain rate of 2.1-3x10(-8) yr(-1) accumulating around the Mabian fault zone. Keeping the weak strength of the fault, numerical results also show that if the central portion of the Xianshuihe-Xiaojiang fault system follows the Daliangshan fault, strain accumulation around the Mabian fault zone could be significantly reduced. It thus can be concluded that the strain partitioning from the weak strength and the special geometry of the Xianshuihe-Xiaojiang fault system must play a crucial role in active deformation around the Mabian area out of the Tibetan plateau deformation domain. This in turn means that in the Xianshuihe-Xiaojiang fault system, the Anninghe-Zemuhe fault is still the main boundary between the southeastern Tibetan plateau and the South China Block.
关键词	XIAOJIANG FAULT SYSTEM COULOMB STRESS EVOLUTION GPS VELOCITY-FIELD SAN-ANDREAS FAULT TIBETAN PLATEAU SOUTHEASTERN MARGIN ACTIVE TECTONICS RUPTURE BEHAVIOR EASTERN BOUNDARY XIANSHUIHE FAULT
英文关键词	Numerical modelling; Rheology and friction of fault zones; Dynamics and mechanics of faulting
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000798346100004
来源期刊	GEOPHYSICAL JOURNAL INTERNATIONAL
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/260583
推荐引用方式 GB/T 7714	Zhu, Xiaojie,He, Jiankun,Wang, Xinguo,et al. Three-dimensional finite element modelling on strain localization around the Mabian earthquake swarm, Sichuan Province[J]. 中国科学院青藏高原研究所,2022,230(3).
APA	Zhu, Xiaojie,He, Jiankun,Wang, Xinguo,&Xiao, Jie.(2022).Three-dimensional finite element modelling on strain localization around the Mabian earthquake swarm, Sichuan Province.GEOPHYSICAL JOURNAL INTERNATIONAL,230(3).
MLA	Zhu, Xiaojie,et al."Three-dimensional finite element modelling on strain localization around the Mabian earthquake swarm, Sichuan Province".GEOPHYSICAL JOURNAL INTERNATIONAL 230.3(2022).