Seismic Rayleigh Wave Method For Localizing And Imaging Subsurface Cavities In Extensively Exploited Districts

This research presents recent developments using seismic Rayleigh waves to detect and image subsurface anomalies. Instead of conventional spectral analysis of surface waves (SASW) method or the multichannel analysis of surface waves (MASW) techniques, this study developed a strategy to isolate Rayleigh waves from raw field data, and apply wavelet transforms to pair-channel analysis of the Rayleigh wave data for dispersion calculation. Finally, a simple steady inversion technique was applied to yield shear velocity as a function of both depth and distance, or shear velocity field (SVF) images, for near surface section display picking. Three locations in the province of Nova Scotia, Canada, with different geological scenarios, were used for seismic investigations: moderately dipping coal seams in the Stellarton Coalfield, steeply dipping gold-bearing veins in the West Waverley Gold District and nearly horizontal strata in Liverpool. The results from the seismic surface wave technique introduced in this research can be evaluated by field observations, documents and borehole logs. The satisfactory interpretations and success of these investigations will result in engineering application for subsurface investigations.