(中南工业大学地球物理勘察新技术研究所，长沙 410083；
中国科学院武汉物理研究所， 武汉 430071)
摘 要: 在三维情况下， 利用B， P， C 坐标系研究了水平多层 介质中导波的能量分布，提出了一种计算大深度处位移和能流密度的方法，避免了精度丢失问题。 在有低速层介质情况 下， 在深入分析瑞利模的基础上，首次研究了陷模的频散及能流分布，分析了它们的传播 机制 。导波能量可能分布在自由表面附近, 表现为面波; 也可能集中在自由界面下某一深度处， 表现为沿低速层延伸方向传播的导波。
关键字: 多层介质 B， P， C坐标系 导波 陷模 瑞利波
（Institute of Applied Geophysics,
Central South University of Technology, Changsha 410083, P. R. China
* Wuhan Institute of Physics, Chinese Academy of Sciences, Wuhan 430071, P. R. China）
Abstract:The energy distributions of guided waves in multilayered media have been investigated in three dimensions in B, P, C coordinate system. A method of calculating the displacement and energy flux density at large depth was presented, and the problem of precision loss was avoided. In the case that a low-velocity medium was included, not only was Rayleigh mode analyzed thoroughly, but also the dispersions and energy distributions of trapped modes were studied for the first time, and their mechanisms were analyzed. The energy of guided waves can concentrate possibly in a little area near the free surface, which is corresponding to the surface wave, and it also possibly concentrates in a depth under the free surface, which is corresponding to a guided wave propagation along the stretching direction of the low-velocity formation.
Key words: multilayered media B, P, C coordinate system guided wave
trapped mode Rayleigh wave
