Crustal and mantle velocity models of southern Tibet from finite frequency tomography | |
Liang, Xiaofeng ; Shen, Yang ; Chen, Yongshun John ; Ren, Yong | |
刊名 | journal of geophysical research solid earth |
2011 | |
关键词 | EAST-WEST EXTENSION INDIAN LITHOSPHERE BENEATH COLLISION ZONE EARTHQUAKES BENEATH SEISMIC TOMOGRAPHY TECTONIC EVOLUTION EURASIA COLLISION UPPERMOST MANTLE GPS MEASUREMENTS 3-DIMENSIONAL P |
DOI | 10.1029/2009JB007159 |
英文摘要 | Using traveltimes of teleseismic body waves recorded by several temporary local seismic arrays, we carried out finite-frequency tomographic inversions to image the three-dimensional velocity structure beneath southern Tibet to examine the roles of the upper mantle in the formation of the Tibetan Plateau. The results reveal a region of relatively high P and S wave velocity anomalies extending from the uppermost mantle to at least 200 km depth beneath the Higher Himalaya. We interpret this high-velocity anomaly as the underthrusting Indian mantle lithosphere. There is a strong low P and S wave velocity anomaly that extends from the lower crust to at least 200 km depth beneath the Yadong-Gulu rift, suggesting that rifting in southern Tibet is probably a process that involves the entire lithosphere. Intermediate-depth earthquakes in southern Tibet are located at the top of an anomalous feature in the mantle with a low Vp, a high Vs, and a low Vp/Vs ratio. One possible explanation for this unusual velocity anomaly is the ongoing granulite-eclogite transformation. Together with the compressional stress from the collision, eclogitization and the associated negative buoyancy force offer a plausible mechanism that causes the subduction of the Indian mantle lithosphere beneath the Higher Himalaya. Our tomographic model and the observation of north-dipping lineations in the upper mantle suggest that the Indian mantle lithosphere has been broken laterally in the direction perpendicular to the convergence beneath the north-south trending rifts and subducted in a progressive, piecewise and subparallel fashion with the current one beneath the Higher Himalaya.; Geochemistry & Geophysics; SCI(E); 13; ARTICLE; 116 |
语种 | 英语 |
内容类型 | 期刊论文 |
源URL | [http://ir.pku.edu.cn/handle/20.500.11897/155823] |
专题 | 地球与空间科学学院 |
推荐引用方式 GB/T 7714 | Liang, Xiaofeng,Shen, Yang,Chen, Yongshun John,et al. Crustal and mantle velocity models of southern Tibet from finite frequency tomography[J]. journal of geophysical research solid earth,2011. |
APA | Liang, Xiaofeng,Shen, Yang,Chen, Yongshun John,&Ren, Yong.(2011).Crustal and mantle velocity models of southern Tibet from finite frequency tomography.journal of geophysical research solid earth. |
MLA | Liang, Xiaofeng,et al."Crustal and mantle velocity models of southern Tibet from finite frequency tomography".journal of geophysical research solid earth (2011). |
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