瑞利波泄漏模式与“之”字形正演模拟

Forward modeling of leaky mode waves and zigzag dispersion curves in Rayleigh waves exploration

对瑞利波勘探中泄漏模式波的求取问题进行模拟研究. 通过添加附加层的方法, 使实频散方程求解瑞利波相速度的范围包含所有的层速度区域, 从而可用导波来模拟计算泄漏模式波.从模拟结果来看, 附加层法不仅能模拟出原模型的实数导波, 还能计算出其泄露模式波的变化;同时, 通过计算vr-λ频散曲线, 说明泄漏模式波的存在也是产生“之”字形现象的原因之一.

How to solve the leaky modes of Rayleigh waves was studied. Appending an appropriate layer under the model, so the solving velocity range included all layers’ Rayleigh wave velocities, and we could calculate the Rayleigh guided waves by Menke and Bixing-Zhang in transfer matrix approach. Calculated Rayleigh leaky mode waves of three models. According to the modeling results, appending layer method can calculate not only the guided waves, but also leaky mode waves. At the same time, it shows that the existing of leaky mode waves can give birth to zigzag dispersion curves.