Distinct velocity variations around the base of the upper mantle beneath northeast Asia
文献类型：期刊论文
| 作者 | Wang, Tao; Chen, Ling |
| 刊名 | PHYSICS OF THE EARTH AND PLANETARY INTERIORS
 |
| 出版日期 | 2009-02-01 |
| 卷号 | 172期号:3-4页码:241-256 |
| 关键词 | 660-km Discontinuity Low-velocity zone under slabs Thermal anomaly Water Northeast Asia |
| ISSN号 | 0031-9201 |
| DOI | 10.1016/j.pepi.2008.09.021 |
| 文献子类 | Article |
| 英文摘要 | Both the global and regional P wave tomographic Studies have revealed significant deep Structural heterogeneities in subduction zone regions. In particular, low-velocity anomalies have been observed beneath the descending high-velocity slabs in a number of subduction zones. The limited resolution at large depths and possible trade-off between the high and low velocities, however, make it difficult to Substantiate this feature and evaluate the vertical extent of the low-velocity Structure. From broadband waveform modeling of triplicated phases near the 660-km discontinuity for three deep events, we constrained both the P and SH wave velocity Structures around the base of the upper mantle in northeast Asia. For the two events beneath the Southern Kurile, the rays traveled through the lowermost transition zone and uppermost lower mantle under the descending Pacific slab. Out preferred models consistently Suggest normal-to-lower P and significantly low SH velocities above and below the 660-km discontinuity extending to about 760-km depth compared with the global IASP91 model, corroborating previous observations for a slow structure underneath the slab. In contrast, both high P and SH velocity anomalies are shown in our preferred models for the Japan subduction zone region, likely reflecting the Structural feature of a slab stagnant above the 660-km discontinuity. The velocity JUMPS across the 660-km discontinuity were found to be on average 4.5% and 7% for P and S waves under the South Kurile, and 3% and 6% under the Japan subduction zone. The respective velocity contrasts in the two regions are consistent with mineralogical models for colder slab interior and hotter under-slab areas. Based on mineral physics data, the depth-averaged similar to 1.5% P and similar to 2.5% SH velocity differences in the depth range of 560-760 km between the two regions Could be primarily explained by a 350-450 K temperature variation, although the presence of about 0.5-1 wt.% water might also contribute to the Subtle velocity variations near the base of the transition zone in the Southern Kurile. From our modeling results, we speculate that the Slow Structure in the Southern Kurile may be Correlated to the low-velocity zone observed previously around the 410-km discontinuity Under Northern Honshu. If this is the case, both may be associated with a thermal anormaly rooted in the lower mantle beneath the subduction zone in northeast Asia. (C) 2008 Elsevier B.V. All rights reserved. |
| WOS关键词 | 660 KM DISCONTINUITY ; SUBDUCTION ZONE ; TRANSITION-ZONE ; SEISMIC DISCONTINUITY ; HYDROUS RINGWOODITE ; ELASTIC PROPERTIES ; HIGH-PRESSURE ; CHINA CRATON ; SOUND VELOCITIES ; MINERAL PHYSICS |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000262801200010 |
| 出版者 | ELSEVIER SCIENCE BV |
| 资助机构 | National Science Foundation of China(40674029 ; National Science Foundation of China(40674029 ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; 90814002) ; 90814002) ; National Science Foundation of China(40674029 ; National Science Foundation of China(40674029 ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; 90814002) ; 90814002) ; National Science Foundation of China(40674029 ; National Science Foundation of China(40674029 ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; 90814002) ; 90814002) ; National Science Foundation of China(40674029 ; National Science Foundation of China(40674029 ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; 90814002) ; 90814002) |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/71420]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Wang, Tao |
| 作者单位 | Chinese Acad Sci, Seismol Lab, SKL LE, Inst Geol & Geophys, Beijing, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wang, Tao,Chen, Ling. Distinct velocity variations around the base of the upper mantle beneath northeast Asia[J]. PHYSICS OF THE EARTH AND PLANETARY INTERIORS,2009,172(3-4):241-256. |
| APA | Wang, Tao,&Chen, Ling.(2009).Distinct velocity variations around the base of the upper mantle beneath northeast Asia.PHYSICS OF THE EARTH AND PLANETARY INTERIORS,172(3-4),241-256. |
| MLA | Wang, Tao,et al."Distinct velocity variations around the base of the upper mantle beneath northeast Asia".PHYSICS OF THE EARTH AND PLANETARY INTERIORS 172.3-4(2009):241-256. |
入库方式： OAI收割
来源：地质与地球物理研究所
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