气候变化领域集成服务门户(CCPortal): Spatial variation in the present-day stress field and tectonic regime of Northeast Tibet from moment tensor solutions of local earthquake data

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DOI	10.1093/gji/ggaa013
	Spatial variation in the present-day stress field and tectonic regime of Northeast Tibet from moment tensor solutions of local earthquake data
	Pan, Zhengyang; He, Jiankun; Shao, Zhigang
通讯作者	Pan, ZY (通讯作者)
发表日期	2020
ISSN	0956-540X
EISSN	1365-246X
起始页码	478
结束页码	491
卷号	221 期号:1
英文摘要	Focal mechanism solutions and their predicted stress pattern can be used to investigate tectonic deformation in seismically active zones and contribute to understanding and constraining the kinematic patterns of the outward growth and uplift of the Tibetan Plateau. Herein, we determined the focal mechanisms of 398 earthquakes in Northeast Tibet recorded by the China National Seismic Network (CNSN) by using the cut-and-paste method. The results show that the earthquakes predominately exhibited thrust and strike-slip faulting mechanisms with very few normal events. We then combined the derived focal mechanisms with global centroid moment tensor (GCMT) catalogue solutions and previously published solutions to predict the regional distribution of the stress field through a damped linear inversion. The inversion results show that most of region is dominated by a thrust faulting regime. From the southern Fact Kunlun fault in the west to the northern Qilian Mountains along the Altyn Tagh fault (ATF), the maximum compression axis rotates slightly clockwise; farther to the south of the IIaiyuan fault in the east, there is an evident clockwise rotation of the maximum compression axis, especially at the eastern end of the Haiyuan fault. In the Qilian Mountains, the axis of the compressive stress orientation approximately trends NE-SW, which does not markedly differ from the direction of India-Eurasia convergence, emphasizing the importance of the compressive stress in reflecting the remote effects of this continental collision. The overall spatial pattern of the principal stress axes is closely consistent with the GPS-derived horizontal surface velocity. A comparison of the stress and strain rate fields demonstrated that the orientations of the crustal stress axes and the surface strain axes were almost identical, which indicates that a diffuse model is more suitable for describing the tectonic characteristics of Northeast Tibet. Additionally, the compressive stress orientation rotated to ENE-WSW in the northern Qilian Mountains along the ATF and to ENE-WSW or E-W along the eastern part of the Haiyuan fault and its adjacent area to the south, highlighting the occurrence of strain partitioning along large left-lateral strike-slip faults or the lateral variation of crustal strength across these faults. Combining geodetic, geological and seismological results, we suggest that a hybrid model incorporating both the diffuse model associated with shortening and thickening of the upper crust and the asthenospheric flow model accounting for the low-velocity zone in the middle-lower crust may reflect the primary mode of crustal deformation in Northeast Tibet.
关键词	LATE CENOZOIC DEFORMATION TERRESTRIAL HEAT-FLOW FAULT PLANE SOLUTIONS STRAIN-RATE FIELDS QILIAN-SHAN CRUSTAL STRUCTURE FOCAL MECHANISMS RECEIVER FUNCTIONS PLATEAU INSIGHTS ACTIVE TECTONICS
英文关键词	Seismicity and tectonics; Continental neotectonics; Kinematics of crustal and mantle deformation
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000525947800034
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/259696
推荐引用方式 GB/T 7714	Pan, Zhengyang,He, Jiankun,Shao, Zhigang. Spatial variation in the present-day stress field and tectonic regime of Northeast Tibet from moment tensor solutions of local earthquake data[J]. 中国科学院青藏高原研究所,2020,221(1).
APA	Pan, Zhengyang,He, Jiankun,&Shao, Zhigang.(2020).Spatial variation in the present-day stress field and tectonic regime of Northeast Tibet from moment tensor solutions of local earthquake data.GEOPHYSICAL JOURNAL INTERNATIONAL,221(1).
MLA	Pan, Zhengyang,et al."Spatial variation in the present-day stress field and tectonic regime of Northeast Tibet from moment tensor solutions of local earthquake data".GEOPHYSICAL JOURNAL INTERNATIONAL 221.1(2020).