| 中国西部三维速度结构及其各向异性 |
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| 引用本文： | 宋仲和,庄真.中国西部三维速度结构及其各向异性[J].地球物理学报,1991,34(6):694-707. |
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| 作者姓名： | 宋仲和 庄真 |
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| 作者单位： | 1. 国家地震局地球物理研究所, 北京 100081;
2. 云南大学地球物理系, 昆明 650091 |
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| 摘 要： | 本文用覆盖中国的358条勒夫面波路径资料,研究了10.45-113.80s范围内中国西部的三维SH波速度结构.结果表明,各构造单元的SH波速度结构均有明显的差别.作为稳定块体的塔里木盆地,壳内重力分异程度较高,上、中、下地壳厚度差别小,壳内无明显的低速层,地壳平均速度比较小;上地幔低速层埋深大且层中速度大;区内横向变化小.构造活动区如天山、青藏高原,其突出的特征是下地壳厚度大且速度大,上地幔盖层速度值相当高.这与西伯利亚、印支板块的挤压有密切的关系.青藏高原东部及其北、东边缘地区壳内存在低速层,上地幔低速层埋深浅,一些地区存在壳幔过渡层.面波各向异性研究表明,青藏高原、天山及印支板块北缘下存在明显的各向异性,以构造边缘地区及上地幔低速层附近最为突出.印度板块、西伯利亚板块与中国大陆间的碰撞引起强大的水平压力和一定的下插作用,是造成青藏高原隆起、地壳增厚、天山隆起的最根本的因素,同时也促成壳幔中辉石、橄榄石的定向排列和物质运移,因而出现明显的各向异性现象.
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| 关 键 词： | 适配滤波频时分析 勒夫波群速度 分格频散反演 中国西部三维速度结构 构造单元 各向异性(VSV-VSH) |
| 收稿时间： | 1990-11-01 |
STUDY ON 3D VELOCITY STRUCTURE AND ANISOTROPY BENEATH THE WEST CHINA FROM THE LOVE WAVE DISPERSION |
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| SONG ZHONG-HE AN CHANG-QIANG CHEN GUO-YING CHEN LI-HUA.STUDY ON 3D VELOCITY STRUCTURE AND ANISOTROPY BENEATH THE WEST CHINA FROM THE LOVE WAVE DISPERSION[J].Chinese Journal of Geophysics,1991,34(6):694-707. |
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| Authors: | SONG ZHONG-HE AN CHANG-QIANG CHEN GUO-YING CHEN LI-HUA |
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| Institution: | 1. Institute of Geophysics, State Seismological Bureau, Beijing 100081;
2. Depertment of Geophysics, Yunnan University, Kunming 650091 |
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| Abstract: | This paper has been studied 3D SH wave velocity structure _beneath the western China, which has been obtained from 358 Love wave mixed-pathes travelling through China's mainland and sea areas with the periods range of 10.45-113.80s. The results indicate that SH wave velocity structure beneath the tectonic elements exist obvious differences one another. As a stable block, the Tarim basin has some higher gravity diffrentiation in the crust, small diffrences between the thiuknesi'es of upper, middle and lower crust, no apparent low velocity layer in crust, smaller average velocity of the crust; great depth of low velocity layer in upper mantle and high velocity in this layer; small lateral variation in this region. In tectonic active area, such as Tianshan, Qinghai-Xizang plateau, the outstanding features are great thickness of lower crust and high velocity, very high velocity of covering layer in upper mantle. This is closely related with compression of Siberian and Indian plates. In the eastren part of Qinghai-Xizang plateau and its north and east marginal regions exist low velocity layer in crust. Shallow depth of low velocity layer in upper mantle and crust-mantle transition layer beneath this marginal regions.The study of surface wave anisotropy indicates, Qinghai-Xizang plateau, Tianshan and the north margin of Indochina plate have clear anisotropy, especially in their marginal regions and low velocity layer of upper mantle. The collision of Indian plate, Seberia plate and China mainland produred the strong horigontal compression and a certain subduction, which is the most basic factor making the uplift of Tainshan, Qinghai-Xizang plateau, tremendous thickness of crust in the latter region, as well as the formation of oreintadon arrangement of the pyroxene and olivine and substance migration in crust-mantle, hence appeared obvious anisotropy. |
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| Keywords: | MF-FTAN technique Love wave group velocity Grid dispersion inversion 3D velocity structure of the western China Tectonic element Anisotropy |
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