| 河西走廊中部地区三维速度结构研究 |
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| 关键词:central Hexi Corridor 3-D velocity structure inversion low-velocity layer |
| 基金项目:地震科学联合基金项目(编号:504004,197025,106086) |
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| 摘要: |
| A study of the 3-D Velocity Structure in Central Hexi Corridor |
| The 3-D velocity tomography image of central Hexi Corridor was obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network. The inversed layering velocity structure does reflect some important features of the deep structure in the study area: ① The velocity of shallow deposition is about 5.006.15 km/s and the vertical velocity gradient is close to 0.15 km/s; the depth of the crystalline basement is about 7 km, with the velocity being 6.15 km/s. ② The depth of the upper crust is some 18 km, with the velocity being 6.33 km/s; the velocity of Minle basin is slightly higher than that of the North Qilian Mountain and the Longshou Mountain. The Alxa block is obviously thrusting under the Hexi Corridor. ③ The bottom of the middle crust is about 30 km in depth with the velocity being 6.58 km/s, and the low-velocity zone is located just between the Qilian Mountain and the Hexi Corridor. ④ The depths of the lower crust imply that the Moho depth is 54 km in the Qilian Mountain, 53.553.0 km in the Minle basin and 52 km in the Alxa block, and that there obviously exists a low-velocity layer of 6.5 km/s at the depth of 3442 km. The research results show that the Longshou Mountain fault may be a reverse one in the upper crust and the Changma-Ebo fault is probably a vertical one reaching the middle crust. |
| DONG Zhi-ping,ZHANG Yuan-sheng.2007.A study of the 3-D Velocity Structure in Central Hexi Corridor[J].Acta Geoscientica Sinica,28(3):270-276. |
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