青藏高原东南缘壳幔耦合强震孕育模型研究  

Crust-Mantle Coupling Model for Seismogenism in the Southeastern Margin of Qinghai-Tibet Plateau

作　　者：侯强 姚亚峰 欧明霖 赵宏[2] 张博康 丁小军 HOU Qiang;YAO Yafeng;OU Minglin;ZHAO Hong;ZHANG Bokang;DING Xiaojun(Faculty of Mechanical and Electronic Information,China University of Geosciences,388 Lumo Road,Wuhan 430074,China;School of Resource Environment and Earth Science,Yunnan University,2 North-Cuihu Road,Kunming 650091,China)

机构地区：[1]中国地质大学(武汉)机械与电子信息学院,武汉市430074 [2]云南大学资源与环境科学学院,昆明市650091

出　　处：《大地测量与地球动力学》2019年第12期1211-1222,共12页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(61601334);中央高校军民融合专项基金培育项目(201708);中央高校基本科研业务费专项资金(CUGL120234)~~

摘　　要：结合青藏高原东南缘软弱带的分布及地震活动性的深度空间特征,提出强震孕育的壳幔耦合模型。利用中国国家数字地震台网和四川云南区域数字地震台网及布设在青藏高原东南缘的地震台站所记录的远震SKS波形资料,通过剪切波分裂得出上地幔各向异性结果数据,描绘出青藏高原东南缘的上地幔各向异性图像;再分别同该地区GPS观测的速度场数据、区域构造应力场数据和13 km深度的介质密度数据进行相关性处理与分析,并针对本文提出的孕震模型进行一定程度的验证。对形变场和应力场耦合特征的研究表明,各向异性的快慢波时间延迟、快波偏振方向总体分别与GPS测量的地壳运动速度场方向变化和水平最大应力方向相关性较大,壳幔各圈层相互作用及软流圈的流动所展示的地震各向异性都与应力传递机制息息相关。通过相关分析可以得到壳内软弱带(低速高导体)在壳幔耦合运动研究中的关键作用,而该类耦合运动与地震孕育息息相关。We focus on the southeastern margin of Qinghai-Tibet plateau,which presents weak distribution characteristics and spatial characteristics of seismicity,and put forward the crust-mantle coupling model of strong earthquake gestation.Using data collected from the China National Digital Seismic Network in Yunnan and Sichuan Regional Digital Seismic Network,and setting in the southeastern margin of Qinghai-Tibet plateau seismic stations teleseismic records by SKS waveform data,through the upper mantle anisotropy results for the shear wave splitting data,we describe the southeastern margin of Qinghai-Tibet plateau in the upper mantle anisotropy images.Then,we carry out correlation processing and analysis respectively with the velocity field data observed by GPS in this area,the data of regional tectonic stress field,and the medium density data at a depth of 13 km.The proposed model is verified to a certain extent.Analysis results show that through the research on the coupling characteristics of the deformation field and stress field,and the anisotropy of fast wave polarization direction with the direction of GPS crustal movement velocity field changes,the maximum stress direction and level of the overall correlation is larger,the mutual effects among various spheres of crust-mantle and asthenosphere shown on the flow of seismic anisotropy are closely related to the stress transfer mechanism.At the same time,we can also get the key role of weak zone(low speed and high conductor)in the study of coupled crust-mantle motion through correlation analysis.

关 键 词：地幔各向异性 地壳应力场 GPS速度场 青藏高原东南缘 壳幔耦合 

分 类 号：P313[天文地球—固体地球物理学] P315[天文地球—地球物理学]