Multilayer densities using a wavelet-based gravity method and their tectonic implications beneath the Tibetan Plateau
Multilayer densities using a wavelet-based gravity method and their tectonic implications beneath the Tibetan Plateau
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基于小波重力法的多层密度及其对青藏高原下方的构造意义
DOI：
10.1093/gji/ggy110
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发表时间：
2018
影响因子：
2.8
通讯作者：
Wu Yihao
中科院分区：
文献类型：
--
作者：
Xu Chuang;Luo Zhicai;Sun Rong;Zhou Hao;Wu Yihao
确定青藏高原的密度结构有助于更好地了解青藏高原的构造结构和发育过程。地震法作为传统方法，在除中部和西部以外的青藏高原地区取得了大量的密度结构成果，但主要受到地震台站覆盖率较差的制约。随着卫星重力任务的实施，重力法由于全球均匀的重力覆盖而更具竞争力。本文开发了一种计算效率高、局部识别能力强的新型基于小波的重力方法来确定青藏高原下方的多层密度。 0~150 km深度反演的六层密度可以揭示研究区丰富的构造结构和发育情况：（1）密度呈顺时针方向分布，西部呈近东西高低交替格局，东部近南北高低交替格局，从全球定位系统速度场来看，与稳定欧亚大陆的地表运动方向几乎垂直； （2）从多层密度可推断出深度约10~110km的明显褶皱结构，其变形方向西部近南北向，东部近东西向； (3) 在多层密度期间，也可以清楚地观察到大约 30 至 110 km 深度的可能河道流动。此外，倒置多层密度与之前的研究一致，验证了我们方法的正确性和有效性。
Determining density structure of the Tibetan Plateau is helpful in better understanding of tectonic structure and development. Seismic method, as traditional approach obtaining a large number of achievements of density structure in the Tibetan Plateau except in the centre and west, is primarily inhibited by the poor seismic station coverage. As the implementation of satellite gravity missions, gravity method is more competitive because of global homogeneous gravity coverage. In this paper, a novel wavelet-based gravity method with high computation efficiency and excellent local identification capability is developed to determine multilayer densities beneath the Tibetan Plateau. The inverted six-layer densities from 0 to 150 km depth can reveal rich tectonic structure and development of study area: (1) The densities present a clockwise pattern, nearly east-west high-low alternating pattern in the west and nearly south-north high-low alternating pattern in the east, which is almost perpendicular to surface movement direction relative to the stable Eurasia from the Global Positioning System velocity field; (2) Apparent fold structure approximately from 10 to 110 km depth can be inferred from the multilayer densities, the deformational direction of which is nearly south-north in the west and east-west in the east; (3) Possible channel flows approximately from 30 to 110 km depth can also be observed clearly during the multilayer densities. Moreover, the inverted multilayer densities are in agreement with previous studies, which verify the correctness and effectiveness of our method.