| 摘要: |
| 使用地震层析成像方法反演了中国台湾地区-菲律宾群岛的1197126条P波震相和1217821条S波震相，首次同时得到了该地区从地表到100km的纵横波速度结构。成像结果揭示了沿着马尼拉海沟向东俯冲的欧亚板块从中国台湾西南部到吕宋岛南端构造形态上的变化；中国台湾中央山脉由于受到造山运动的影响，地壳厚度可达55～60km，而山脉两侧的地壳厚度多为20～35km；此外，成像结果还提供了菲律宾海板块在中国台湾东北部及琉球海沟下方北向俯冲的地球物理学证据；研究区域南部的菲律宾群岛由于同时受到两侧欧亚板块和菲律宾海板块的双向俯冲，使得岛内的岩石圈变形严重，岛弧岩浆和地震活动十分发育；群岛东侧的菲律宾海板块在东吕宋海槽的活动性较弱，很可能是本哈姆海台的碰撞和俯冲所造成的，而菲律宾海板块在菲律宾海沟的俯冲活动则十分强烈，随着深度的增加逐渐向南发展。研究表明，板块俯冲造成了中国台湾地区-菲律宾群岛的地壳及上地幔具有较强的不均一性，这不仅孕育了大量的地震和火山活动，同时也对该地区的地质构造产生了深远的影响。 |
| 关键词: 中国台湾地区-菲律宾群岛 地震层析成像 纵横波速度结构 岛弧岩浆活动 |
| DOI： |
| 分类号:P315 |
| 基金项目:国家自然科学基金项目（41572201，41372229）、全球变化与海气相互作用（GASI-GEOGE-05-02）、中国科学院百人计划项目（17314059）共同资助 |
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| The vP and vS Tomography of the Taiwan, China-Philippine Archipelago and Its Tectonic Implications |
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Tan Haoyuan, Wang Zhi
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Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
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| Abstract: |
| We,for the first time,inverted the VP and VS velocity structure simultaneously in the Taiwan, China-Philippine archipelago subducting system from surface to 100km depth using 43933 P-wave events and 44667 S-wave events. Our tomographic results demonstrate the pattern of Eurasian Plate which subducts eastward from southwest of Taiwan, China to south of Luzon Islreas which reduces to 20~35km depth on its flanks. Our results could provide the evidence of the Philippine Plate subducts northwestward beneath northeast of Taiwan, China and Ryukyu Trench. Beneath Philippine archipelago,severe lithosphere deformation leading to an intensive magmatism and seismic activity can be seen in crust which can be ascribed to the bidirectional subduction of Eurasian Plate and Phillipine Sea Plate. Relative weak activity of the Philippine Sea Plate on East Luzon Trough which may be due to the collision and subduction of Benham Rise,in a sharp contrast that strong subduction occurs at the Philippine Trench which shifts southward with the depth increases. Our study suggests that structural heterogeneities in the crust and upper mantle along the Taiwan, China-Philippine archipelago subducting system play a crucial role in not only generations of earthquake and magmatism but also formation of the distinct tectonic framework. |
| Key words: Taiwan, China-Philippine archipelago Seismic tomography vP and vS velocity structure Island arc magma activity |
