| 雷琼拗陷地壳结构特征 |
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| 引用本文： | 嘉世旭, 李志雄, 徐朝繁, 沈繁銮, 赵文俊, 杨卓欣, 杨键, 雷宛. 雷琼拗陷地壳结构特征[J]. 地球物理学报, 2006, 49(5): 1385-1394, |
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| 作者姓名： | 嘉世旭 李志雄 徐朝繁 沈繁銮 赵文俊 杨卓欣 杨键 雷宛 |
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| 作者单位： | 1 中国地震局地球物理勘探中心,郑州 450002 2 海南省地震局,海口 570203 3 成都理工大学信息工程学院,成都 610059 |
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| 基金项目： | 地震科学联合基金，海南省地震局资助项目，中国地震局资助项目 |
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| 摘 要： | 根据1984～1985年在雷琼地区完成、长约210 km的白延—江洪深地震测深资料，应用有限差分法、时间项法反演和二维非均匀动力学射线追踪等方法，得到白延—江洪地壳剖面的二维非均匀构造图像.结果显示：琼北及雷州半岛地壳厚约25～26 km，地壳平均速度在琼州海峡南段琼北凸起约6.16 km·s-1，海峡北段雷琼拗陷区约5.70 km·s-1；地壳速度偏低，下地壳尤为明显，仅约6.3～6.5 km·s-1；结晶基底显示为厚约2～4 km、速度5.5～6.0 km·s-1的速度梯度带，Moho界面上、下界面速度分别是6.5 km·s-1和8.05 km·s-1的一级速度间断面，没有发现明显的壳幔过渡带.白延—江洪剖面位于雷琼拗陷更新世玄武岩覆盖区，推测地壳厚度减薄以及低速度构造主要反映了该区域自新生代以来一直延续至第四系晚期的多期火山岩浆喷发热地幔对地壳底部的底浸、拆层与地壳仍处于相对温热状态相关.
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| 关 键 词： | 雷琼拗陷 深地震测深 地壳构造 低速结构 |
| 文章编号： | 0001-5733（2006）05-1385-10 |
| 收稿时间： | 2005-03-03 |
| 修稿时间： | 2005-03-032006-05-16 |
Crustal structure features of the Leiqiong depression in Hainan Province |
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| JIA Shi-Xu, LI Zhi-Xiong, XU Zhao-Fan, SHEN Fan-Luan, ZHAO Wen-Jun, YANG Zhuo-Xin, YANG Jian, LEI Wan. Crustal structure features of the Leiqiong depression in Hainan Province[J]. Chinese Journal of Geophysics (in Chinese), 2006, 49(5): 1385-1394, |
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| Authors: | JIA Shi-Xu LI Zhi-Xiong XU Zhao-Fan SHEN Fan-Luan ZHAO Wen-Jun YANG Zhuo-Xin YANG Jian LEI Wan |
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| Affiliation: | 1 Geophysical Prospecting Center, China Earthquake Administration, Zhengzhou 450002, China 2 Earthquake Administration of Hainan Province, Haikou 570203, China3 College of Information Engineering, Chengdu University of Techology, Chengdu 610059, China |
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| Abstract: | Seismic data obtained from an about 210 km long Baiyan Jianghong deep seismic sounding profile, which was completed in Leiqiong area in 1984 and 1985, were processed by means of finite difference tomography, time term inversion and 2 D dynamic ray tracing methods. And 2 D inhomogeneous crustal structure images along Baiyan Jianghong seismic line were determined. The results show that the crustal thickness in northern Hainan province and Leizhou Peninsula is about 25～26 km. In northern Hainan island embossment of the southern part of Qiongzhou Straits, the average crustal velocity is about 616 km·s-1 and 570 km·s-1 in the Leiqiong depression of northern segment of Qiongzhou Straits. The crustal velocity is particular low and especially obvious in lower crust where it is only about 63～65 km·s-1; The crystalline basement presents a velocity gradient belt, the thickness of which is about 2～4 km and the velocity is approximately 55～60 km·s-1. Moho, the velocities of which on its two sides are 65 km·s-1 and 805 km·s-1 respectively, shows one_order velocity discontinuity, and there is no obvious crust mantle transitional zone to be found. Because the Baiyan Jianghong seismic line lies in the Leiqiong depression area with basalt covering of the Pleistocene, it is suggested that the thinner crust and lower velocity in this area mainly reflect the multi erupting of volcanic magma from the Cenozoic till the late Quaternary as well as the underplating and delaminating of hot mantle to the crustal bottom which are interrelated with the crust be still in comparatively hot state. |
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| Keywords: | Leiqiong depression Deep seismic sounding Crustal structure Low velocity structure |
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