Temporal and spatial variation of b-value before and after Wenchuan earthquake and its tectonic implication

doi:10.6038/cjg20170607

	Temporal and spatial variation of b-value before and after Wenchuan earthquake and its tectonic implication
	Liu, YB (Liu Yan-Bing)1,2; Pei, SP (Pei Shun-Ping)2; Pei, SP
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2017
卷号	60 期号:6 页码:2104-2112
关键词	LONGMENSHAN TOMOGRAPHY RELOCATION SEQUENCE CHINA
DOI	10.6038/cjg20170607
文献子类	Article
英文摘要	Seismic b-value shows close relationship with stress, with high stress corresponding to low b-values. Research on temporal and spatial variation of b-value in Longmenshan area will provide useful information to understand stress evolution of Wenchuan earthquake. In this paper, we relocated the earthquakes in Longmen Shan region before and after the Wenchuan earthquake (M(S)8. 0) by both joint inversion of hypocenter location and velocity structure and the double difference earthquake location method, and then calculated temporal variation of the b-value in entire region and its spatial distribution in different time periods before and after Wenchuan earthquake. The results show: (1) The b-values show a significant boundary at depth of similar to 15 km, above which the b-value is much higher than that blow 15 km. This boundary indicates the division between brittle and ductile layers in the upper crust. (2) Temporal variation of average b-value shows clear decrease after the Wenchuan Earthquake, and then gradually increases till Lushan earthquake, however decreases again after the Lushan Earthquake. This variation trend represents not only the co-seismic change but also healing process of the Longmenshan fault. (3) Spatial variation of b-value shows increase (i.e. decreased stress) in Wenchuan rupture zone after Lushan earthquake that reveals possible ductile deformation in the gap between the Lushan and the Wenchuan earthquake and the Lushan earthquake promoted the healing of the rupture zone of the Wenchuan earthquake. (4) The significant low b-value anomaly in the Pengguan complex rock area near Yingxiu before Wenchuan earthquake suggests high differential stress in this region and therefore maximum dislocation occurred here after the Wenchuan Earthquake.
学科主题	地球物理学
WOS研究方向	Geochemistry & Geophysics
语种	英语
WOS记录号	WOS:000403744600007
内容类型	期刊论文
源URL	[http://ir.itpcas.ac.cn/handle/131C11/8204]
专题	青藏高原研究所_图书馆
通讯作者	Pei, SP
作者单位	1.Univ Chinese Acad Sci, Beijing 100049, Peoples R China. 2.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Continental Collis & Plateau Uplift, Beijing 100085, Peoples R China.
推荐引用方式 GB/T 7714	Liu, YB ,Pei, SP ,Pei, SP. Temporal and spatial variation of b-value before and after Wenchuan earthquake and its tectonic implication[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2017,60(6):2104-2112.
APA	Liu, YB ,Pei, SP ,&Pei, SP.(2017).Temporal and spatial variation of b-value before and after Wenchuan earthquake and its tectonic implication.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,60(6),2104-2112.
MLA	Liu, YB ,et al."Temporal and spatial variation of b-value before and after Wenchuan earthquake and its tectonic implication".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 60.6(2017):2104-2112.