【摘要】 纵横波联合勘探可以得到更多关于岩石圈层岩性、物性等介质属性方面的信息,有效提高地壳物质组成的约束性.在纵波速度结构模型的基础上,通过射线追踪和走时拟合对OBS2006-3地震剖面径向分量的转换震相进行了横波速度结构模拟.结果表明:沉积层1、沉积层2的横波速度分别为0.7～0.9 km/s和1.6～1.7 km/s,波速比由2.64～3.16变化到2.41左右,较高的波速比表明沉积层固结程度不高;中生代沉积层横波速度由浅部的2.6 km/s增大到3.0 km/s,波速比为1.74～1.80;地壳中波速比为1.74～1.82,表明该剖面地壳为陆壳性质;下地壳高速层的横波速度为4.0～4.2 km/s,纵横波速比为1.73～1.78,揭示高速层的物质组成为铁镁质的基性岩,推断其与海底扩张停止之后的岩浆底侵作用有关.更多还原

【Abstract】 The joint exploration of P-wave and S-wave can obtain amount of information on lithology and geophysical properties,which effectively improve the composition constraint of the deep crustal structure.Based on the optimum P-wave model,the shear waves recorded on the radial components of profile OBS2006-3 have been modeled by 2-D 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 the V_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.更多还原