| 东亚及西太平洋地壳上地幔P波三维速度结构 |
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| 作者姓名： | 瞿辰 周蕙兰 |
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| 作者单位： | 中国科学院研究生院, 北京 100049 |
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| 基金项目： | 国家自然科学基金(40234047;40374009)资助 |
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| 摘 要： | 利用ISC报告中170550条P波到时资料(地震数为12500,台站数为928个,且地震和台站都分布在研究区内),对东亚及西太平洋边缘海(60°E～150°E,10°S～60°N)的深至300km的地壳上地幔三维速度结构进行了研究,分辨率达2°×2°.初步结果表明:(1)在研究区域内东西两部分的岩石圈与上地幔低速带的结构有非常明显的差异.横向上大体以108°E为界,纵向上以90km深度为界,东部与西部P波速度结构差异较大.西部是岩石圈汇聚增厚区,东部是岩石圈拉张减薄区.西部上地幔低速带不发育,东部低速带比西部厚.(2)青藏高原地壳岩石圈巨厚,上地幔低速带不明显.印度次大陆岩石圈板片以低角度下插到青藏高原之下.(3)日本海和菲律宾海地壳之下有高速体,可能是太平洋板块向东俯冲产生的.
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| 关 键 词： | 东亚及西太平洋边缘海 地壳上地幔 P波三维速度结构 |
| 收稿时间： | 2004-07-30 |
| 修稿时间： | 2004-11-25 |
P-Wave Velocity Structure of Crust and Upper Mantle in East Asia and West Pacific Marginal Seas |
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| Authors: | QU Chen ZHOU Hui-Lan |
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| Institution: | Graduate School, Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | 3-D velocity structure of crust and upper mantle beneath the East Asia and West Pacific marginal seas (60bE~ 150bE, 10bS~ 60bN) down to the depth of 300km has been studied by using a total of 170550 P-wave first arrival times from the ISC bulletin, which are selected from 12500 events and 928 seismic stations within the studying areas. The result is given with the resolution of grid spacing of 2b@ 2b. The preliminary results show: (1) The P-wave velocity structure is so different between the eastern part and western part of the East Asia and West Pacific marginal seas by the boundary of 108bE. The western part isthe thickening convergent lithosphere caused by Indian subcontinent colliding with the Eurasian continent, and the eastern part is a disassembly causing the lithosphere thinning and extension arising from intrusion of asthenospheric material. (2) The crust and lithosphere of the Tibet is very thick, and the LVZ is not obvious. The Indian subcontinent dived to the beneath of the Tibet. (3) There are the high-velocity anomalies beneath the Japan Sea and the Philippines Sea. It could be the evidence that the Pacific slab dived to this area. |
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| Keywords: | the East Asia and West Pacific marginal seas the crust and the upper mantle P-wave 3-D velocity structure |
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