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

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.