High-Resolution Seismic Tomographic Imaging: A Case Study from Kuala Lumpur, Malaysia

An integrated P- and S-wave cross-borehole tomographic survey was performed in the city center of Kuala Lumpur, Malaysia, with the aim of exploring a karstic limestone area near an area that previously encountered cavities. High quality sparker signals were generated to record P-waves. Additonally, horizontally polarized S-waves were generated with two opposing, perpendicular strike directions and recorded with a multi-level, three component receiver array. The P- and S-wave traveltimes were used to invert for two tomograms. The tomograms enabled the calculation of the elastic parameters, i.e., P- to S-wave velocity (Vp/Vs) ratio, Poisson’s ratio, bulk modulus, Young’s modulus and the shear modulus, on a 2D surface between the boreholes. The interpretation of the tomograms was constrained by two additional boreholes, which provided more confidence on the delineation and location of cavities at depths. The survey shows the benefit of co-locating P- and S-wave tomography surveys.