ELASTIC APPROACH TO REMOVE SURFICIAL WAVES FROM SHOT GATHERS

Earth sciences research journal

MALAVER, LUIS LEONARDO¹  MONTES, LUIS ALFREDO¹ 

[1] Universidad Nacional de Colombia

关键词: Ground roll;    wave equation;    finite differences;    modeling;    filters.;   

DOI  :  

学科分类：天文学(综合)

来源: Universidad Nacional de Colombia * Departamento de Geociencias

【 摘 要 】

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.

【 授权许可】

CC BY