The paper presents an application of 2-D time-domain waveform tomography for detection of embedded voids/anomalies. The measured seismic surface wave fields were inverted using a full waveform inversion (FWI) technique, based on a finite-difference solution of 2-D elastic wave equations and Gauss-Newton inversion method. The key advantage of this approach is the ability to generate all possible wave propagation modes of seismic wavefields (body waves and Rayleigh waves) that are then compared with measured data to infer complex subsurface properties. Both the pressure wave (P-wave) and shear wave (S-wave) velocities are inverted independently and simultaneously for possible indication of soil types. The inversion results of real data set show that the waveform analysis was able to delineate a complex profile with an embedded void and highly variable bedrock both laterally and vertically. Independent invasive test (standard penetration test, SPT) was also conducted to verify the seismic test results.
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