Impact of clutter waves on surface-wave analysis under short alignment and a clutter waves removal method

Abstract

Active source surface-wave exploration has become one of the common methods for obtaining shallow urban subsurface structures. The method offers the advantages of being non-destructive, easy to operate, and providing reliable results. Obtaining accurate dispersion curves is a key factor for the successful application of this method. Currently, most researchers believe that surface wave energy constitutes a large proportion of the seismic records, while the energy of other seismic waves (such as body waves) is relatively small. Therefore, there is no need to remove clutter waves other than surface waves when calculating surface wave dispersion. However, this paper compares the effects of dispersion imaging obtained with and without clutter wave removal through numerical simulations and field tests. The results indicate that when the measurement alignment is short (generally less than 20 m), clutter waves can cause varying degrees of “distortion” in the dispersion curves, deviating from the real dispersion curves. Conversely, after removing clutter waves, the “distortion” can be corrected, leading to more accurate dispersion imaging. Therefore, we recommend conducting clutter removal processing when the measurement alignment is short. This paper proposes a stable and feasible clutter wave removal method that can effectively suppress clutter interference and improve the accuracy of dispersion imaging. The research in this paper provides an alternative and optimized solution for the pre-processing of near-surface active source surface-wave exploration.