Surface waves: Use them then lose them. Surface-wave analysis, inversion and attenuation in land reflection seismic surveying

摘要

While in other domains of applied geophysics the surface-wave is considered a source of information for near-surface characterization, in the seismic industry the so-called ground roll has been traditionally regarded only as coherent noise to be filtered out as soon as possible. This difference of perspective is mainly due to the limitations of conventional land acquisition. The Rayleigh waves, which constitute a large part of the recorded energy, can be acquired properly, analysed and inverted to characterize the near-surface with a surprisingly high resolution, even in large 3D surveys, with point receiver acquisition. Surface waves can play a new role: they contribute to a better nearsurface characterization for the perturbation correction and can be used for velocity modelling and geological modelling. Their proper identification enables alternative filtering strategies. Surface waves are not coherent noise but a signal that can be lifted from the seismic record and exploited in a variety of well-established geophysical solutions. In this paper we discuss a workflow for the analysis, inversion and attenuation of surface waves with 3D land data, showing examples from a land 3D survey in Egypt.