SUMMARY

P seismic wave velocity model of Southeast Asian lithosphere and mantle

Cao Đình Triều, T. Svetkova, Bùi Anh Nam,
Nguyễn Đức Vinh, Thái Anh Tuấn

The method of Taylor approximation for solution of seismic tomography problem has been used to construct P seismic wave velocity (V_P) model of SE Asian lithosphere and mantle. Some conclusions can be made as follows:

1. The average V_P of the top of mantle is 7.80 - 8.10 km/s. The high values of V_P (8.00 - 8.10 km/s) coincide with the ocean crust: centre of East Sea (VN), Philippines Sea, and Indian Ocean. V_P of the asthenosphere is 8.10 - 8.40 km/s and reaches the value of 8.00 - 8.10 km/s at the centre of East Sea (VN), Philippines Sea, and Indian Ocean. Low V_P values (8.10 - 8.20 km/s) belong to the areas of Northwest Vietnam, North of Sulawesi Island and Cocost Island.

2. The average V_P of the lower part of upper mantle are 8.40 - 8.70 km/s; lower P_P (8.40 - 8.60 km/s) coinciding with the ocean crust. The continental structures, such as Trường Sơn, Khorat, Kon Tum, Đà Lạt, have also low P seismic wave velocity, less than 8.60 km/s. The transition layer has the V_P equal 9.40 - 9.70 km/s. The upper part of the lower mantle has the V_P = 10.60 - 10.90 km/s. The V_P of the tectonosphere increases with the depth and is stable with the lateral direction. From the depth of 1800 to 2500 km the V_P changes very complicatedly with the vertical and lateral directions.

Ngày nhận bài: 10/9/2009

Người biên tập: PGS.TS Nguyễn Hồng Phương

(Viện Vật lý Địa cầu, Viện KH&CN Việt Nam).