Multimodal Analysis Of High Frequency Surface Waves

Surface waves on a multi-channel record are converted directly into images of multimode<br>dispersion curves through a simple wavefield transformation method. Pre-existing multichannel<br>processing methods require preparation of a shot gather with exceptionally large number<br>of traces that cover wide range of source-to-receiver offsets for a reliable separation of different<br>modes. The method described here constructs high-resolution images of dispersion curves with<br>relatively small number of traces. This method is best suited for near-surface engineering<br>project where surface coverage of a shot gather is often limited to near-source locations and<br>higher-mode surface waves can be often generated with significant amount of energy.<br>Performance of the method is illustrated through tests using both real and synthetic data.