Abstract

MALAVER, LUIS LEONARDO  and  MONTES, LUIS ALFREDO. ELASTIC APPROACH TO REMOVE SURFICIAL WAVES FROM SHOT GATHERS . Earth Sci. Res. J. [online]. 2005, vol.9, n.1, pp.65-69. ISSN 1794-6190.

This paper presents a deterministic two-step approach for the attenuation of ground-roll: modeling the ground-roll response and subtracting it from the recorded shot gather. The first step requires an elastic model of the shallow subsurface, which is created by estimating the p-wave velocity from the first arrivals or uphole times and the s-wave velocity from the ground-roll itself. A finite difference program simulates the elastic wave propagation in the model, providing both an acoustic seismogram and elastic one which contains the ground-roll and also the acoustic response. The provided seismograms are numerically subtracted trace by trace to furnish the isolated ground-roll. The method was applied to records from a Colombian foothill area . These records are contaminated with strong, dispersive, spatially aliased ground-roll that overwhelms the subsurface reflections. The results show that the method provides a better attenuation of ground-roll than those standard techniques such as low-cut frequency filters or f-k filtering, but it does so without sacrificing the low frequency component of data and without causing any distortion in seismic signal .

Keywords : Ground roll; wave equation; finite differences; modeling; filters.

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