Surface-wave full waveform inversion for short-offset acquisition: A method for fine-scale characterization of shallow geological structures

Abstract Accurate characterization of shallow subsurface structures is important for urban development and hazard mitigation, but geophysical investigations in developed areas are often constrained by limited space and short source–receiver offsets. Under such conditions, conventional methods such as multichannel analysis of surface waves (MASW) may become less effective. Surface-wave full-waveform inversion (SWFWI) provides an alternative because its probing depth depends mainly on the lowest usable frequencies rather than on long offsets, making it suitable for short-offset applications. Performance under such conditions was evaluated through synthetic experiments and a field-data application. The synthetic results show that SWFWI can recover the main target anomalies and stratigraphic features under short-offset conditions, whereas the corresponding MASW result does not resolve these structures adequately. Because surface-wave dispersion is less severe and the waveforms are relatively simple in short-offset configurations, the conventional L2-norm objective function remains effective in this setting. Comparative tests with the global correlation norm (GCN) show that the L2-norm objective function performs well under ideal amplitude-consistent conditions, whereas GCN is more robust when couplingrelated amplitude inconsistencies are present; under such conditions, trace-by-trace normalization improves the performance of the L2-norm objective function. Field-data inversion recovers a broadly consistent three-layer subsurface framework and improves the fit to the observed data, indicating that SWFWI is applicable under realistic short-offset acquisition constraints.