用九分量折射波研究低降速带

为了研究转换波的采集方法，同时获取准确的静校正数据，在江陵凹陷西北部玄武岩发育区布设了一条转换波广角勘探试验测线。在同条测线上分段做了九分量折射波地震采集试验，采用自已研制的横波激发器来激发SV波和SH波，用小药量激发P波，使用单个三分量检波器记录数据，采集到了较好的P波、SV波和SH波初至数据。解释结果说明，在潜水面上有较强烈的P波反射，而横波在潜水面附近没有反射，潜水面上vP/vS的值为2.28;在潜水面下的风化带内, vP/vS的值为6.8;在基底老地层中,vP/vS的值为5.6。在深度为27m的风化带内,静校正量P波为50ms，SH波为220ms，SV波为133ms。

Study of low velocity layer via 9-component refraction survey

To investigate the method of converted-wave data acquisition and gather accurate static information, a wide-angle tentative seismic line was shot in the basalt development zone in northwestern Jiangling depression. 9-component refraction survey was also conducted segmentally along the line. Self-made energizer is used to generate SV- and SH-waves > small dose of dynamite is used to produce P-waves. Data are recorded by single 3-compo-nent geophones. P-waves are observed at the top of water table and no S-wave is observed around the water table. The ratio of vp to vs is 2. 28 at the top of water table, 6. 8 in the weathering zone below the water table, and 5. 6 in the basement. The statics are 50ms,220ms,and 133ms respectively for P-waves, SH-waves, and SV-waves in the weathering zone at depth of 27m.