Acquisition of active multichannel analysis of surface waves (MASW) data in karst terrain

This study was designed to verify the effects and data reproducibility when the length of receiver array, receiver spacing, source offset and array orientation parameters are changed for data acquired using multichannel analysis of surface waves (MASW), at intended target depth of 30ft (9m), and to compare the results with electrical resistivity tomography (ERT) data obtained for the same study site. The MASW data acquired for 34 sites, along four profiles for each site using variable source offsets of 10ft (3m) and 30ft (9.1m), and variable receiver spacings of 2.5ft (0.76m) and 5.0ft (0.76m), concurrently. Out of the 272 profiles studied, 136 profiles were oriented east-west, and 136 profiles were oriented north-south. The MASW data was used in conjunction with ERT data to ensure the accuracy of the ERT data. The comparative analysis indicated the profile configuration measurements have significant influence on the quality of the data and that the best inversion analysis is obtained when the dispersion curves are created using the north-south oriented arrays. The MASW survey study concluded that the most consistent and beneficial karst terrain dispersion images were those obtained from the predicted optimal acquisition, using receiver spacing (dx) = 2.5ft, source offset (X1) =10ft and depth of investigation of about 30ft --Abstract, page iii