利用体波层析成像技术研究欧亚及邻区地幔三维速度结构

The 3-D velocity structures of the Eurasian mantle based on the body wave tomography

根据体波层析成像技术,利用大量走时数据,做出0°～180°E,30°S～90°S范围内0～2889km深的三维速度分布图像,得到欧亚地区局部区域岩石圈及地幔的高分辨率速度结构,并从地球动力学角度出发对这些成像结果做进一步解释。

About 7 000 000 travel time data for 1964-1997 from ISC were used to construct the images of the 3D velocity distribution within the context of 0° -180°E and 30°S-90°S at the depths from 0 km to 2 889 km, and the images of the highresolution velocity structures of the lithosphere and mantle in the Eurasian area. The results of research show that: (1) the highvelocity anomalies appear in the upper part of the Upper Mantle (depth<530 m) throughout the Eurasian plate, suggesting an Eurasian continental root and a higher velocity of the continental lithosphere than that of the oceanic lithosphere in this part of the mantle; (2) the NW-SEtrending Tethyan tectonic zone is observed in the Middle Mantle (at the depths of 900 -1 800 km); (3) the highvelocity anomalies occur in eastern China and its neighbouring sea areas, while the lowvelocity anomalies appear in the East Afria rift and western Indian Ocean, and (4) the decreasing seismic wave velocities at the coremantle boundary indicate a stronger effect of high temperatures of the core.