| 菲律宾群岛深部速度结构成像与双向俯冲板片构造特征 |
| |
| 引用本文： | 谭皓原,王志.菲律宾群岛深部速度结构成像与双向俯冲板片构造特征[J].地球物理学报,2018,61(12):4887-4900. |
| |
| 作者姓名： | 谭皓原 王志 |
| |
| 作者单位： | 1. 中国科学院南海海洋研究所, 边缘海与大洋地质重点实验室, 广州 510301;2. 中国科学院大学, 北京 100049 |
| |
| 基金项目： | 国家海洋局全球变化与海气相互作用国际合作项目（GASI-GEOGE-05-02），国家自然科学基金项目（41572201，41372229），中国科学院百人计划（17314059）资助. |
| |
| 摘 要： | 菲律宾群岛受到欧亚板块、菲律宾海板块和印度-澳大利亚板块的碰撞作用，地质环境复杂，构造因素多样.尽管近几年来已经有了少数关于该区域层析成像的研究，但这些研究的区域主要集中在马尼拉海沟、吕宋岛及中菲律宾地区，而关于群岛周围其他海沟和南菲律宾地区的讨论相对较少.到目前为止，还没有同时获得过关于菲律宾群岛深部纵、横波速度结构的研究，本次研究通过反演155779条P波震相和59642条S波震相，同时获得了菲律宾群岛从地表至150 km深度的纵、横波速度结构.地震层析成像结果表明该地区的壳幔速度结构具有较强的不均一性，地壳内部存在着广泛的低速异常，而表征俯冲板块的高速异常则沿着群岛周边的海沟展布.南海块体在马尼拉海沟中段的俯冲角度和俯冲活动性比南段小；菲律宾海板块在东吕宋海槽南段微弱的俯冲作用很有可能同本哈姆海台的碰撞有关.菲律宾群岛大部分MW>6.0的强震沿着各个板块的边界发生，体现出菲律宾海板块同欧亚板块之间的强耦合作用，群岛西侧的南海块体在马尼拉海沟16°N-20°N之间呈现出的弱耦合状态可能跟北吕宋地区的拉张应力环境有关，南海块体在16°N以南的地区同上覆块体之间的耦合作用较强；群岛东侧的菲律宾海板块在14°N以北的地区没有强震发生，它与菲律宾群岛之间的耦合程度从北向南逐渐增强，在12°N以南的地区要强于12°N以北的地区；此外苏禄海盆和菲律宾构造带之间也存在着强耦合关系.
|
| 关 键 词： | 地震层析成像 马尼拉海沟 双向俯冲 P波和S波速度结构 板块耦合 |
| 收稿时间： | 2018-04-27 |
Seismic velocity imaging and tectonic characteristics of the bidirectional subducting slabs under Philippine Archipelago |
| |
| TAN HaoYuan,WANG Zhi.Seismic velocity imaging and tectonic characteristics of the bidirectional subducting slabs under Philippine Archipelago[J].Chinese Journal of Geophysics,2018,61(12):4887-4900. |
| |
| Authors: | TAN HaoYuan WANG Zhi |
| |
| Institution: | 1. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;2. University of Chinese Academy of Sciences, Beijing 100049, China |
| |
| Abstract: | The complicated geological settings and tectonics of the Philippine Archipelago is mainly caused by the convergence of the Eurasian, the Philippine Sea and the Indian-Austrian plates. Although a few seismic tomographic studies have been conducted in the Philippine Archipelago, most of them focused on the Manila Trench, Luzon Island arc and the middle Philippine. So far few P-and S-wave tomographic studies in the crust and upper mantle of the Philippine Archipelago and its surrounding regions have been carried out.We obtained VP and VS velocity structures of Philippine Archipelago for the first time by inverting 155779 P-wave rays and 59642 S-wave rays simultaneously. Our seismic tomography shows strong heterogeneities seated in the crust and upper mantle beneath Philippine Archipelago. Widely spread low velocity anomalies emerge in the crust which may be caused by dehydration of oceanic crusts and sediments whereas high velocity anomalies extend along trenches around Philippines. Smaller dip angle and weaker subduction activity in the middle part of South China Sea Plate than the south part are shown. Little subduction can be seen in the south terminal of East Luzon Trough and northern part of Philippine Trench, which could be ascribed to the subduction of Benham Rise. We therefore suggest that strong coupling between Philippine Sea Plate and Eurasia Plate is revealed by the occurrence of MW>6.0 earthquakes along plate boundaries, weak coupling between 16°N to 20°N in South China Sea slab along Manila Trench might be caused by the extensional stress in north Luzon, on the contrary, strong coupling are shown south of 16°N. On the east side of Philippine Archipelago, no big earthquake occurred north of 14°N in the Philippine Sea Plate, interpolate coupling becomes stronger from north to south, coupling extent is much bigger to the south of 12°N than to the north. Besides, strong coupling exists between Sulu Sea basin and Philippine Mobile Belt too. |
| |
| Keywords: | Seismic tomography Manila Trench Bidirectional subduction VP and VS structure Interplate coupling |
|
| 点击此处可从《地球物理学报》浏览原始摘要信息 |
| 点击此处可从《地球物理学报》下载免费的PDF全文 |
|
