• 责任者：Wei Xiaodong (Key Laboratory of Marginal Sea Geology ; South China Sea Institute of Oceanology ; Chinese Academy of Sciences ; Guangzhou 510301 ; China) ; Zhao Minghui
• 刊名：Chinese Journal of Geophysics
• 出版年：2011
• 卷期：54(12)
• 关键词：下地壳 ; lower crust ; 横波 ; S-waves ; 速度结构 ; velocity structure ; 南海 ; South China Sea
• 页码：p.3150-3160
• 图表：7 illus., 2 tables, 36 refs.
• 分类号：0400
• 出版序号：20122230
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

Based on the optimum P-wave model, the shear waves recorded on the radial components of profile OBS2006-3 have been modeled by 2D ray-tracing. The S-wave velocities in sedimentary layer 1 and sedimentary layer 2 are of 0.7～0.9 km/s and 1.6～1.7 km/s,  respectively. The V_p/V_s ratios in these sediments vary from 2.64～3.16 to 2.41. The relatively high V_p/V_s ratios are probably related to unconsolidated sediments. In the Mesozoic sedimentary layer, the S-wave velocity increases gradually from 2.6 km/s at the top to 3.0 km/s at the bottom, and theV_p/V_s  ratio is of 1.71～1.80.The V_p/V_s ratio of 1.74～1.82 in the crust is considered to be the continental crust. The S-wave velocity and V_p/V_s  are 4.0～4.2 km/s and 1.73～1.78 of the High Velocity Layer (HVL) in the lower crust, which suggest that the HVL has a mafic composition that may originate from underplating of the igneous rocks after the cessation of the seafloor spreading.