Avanços na Pesquisa em Ciências Aplicadas Acesso livre

Abstrato

Joint inversion of high resolution seismic reflection data and seismic refraction tomography model to illuminate the very near surface structures

Collins C. Chiemeke and Chioma N. Modebe

Information within less than 50 ms of seismic reflection data are often masked by surface wave. These amplitude and velocity information within this region are needed to delineate the very near surface structure and for proper static correction of reflection seismic data. This research was carried out with a bid to developing a technique that could solve the problems of near surface reflection within the upper low velocity zone. High resolution seismic reflection data was carried out using split spread techniques to characterise the subsurface structure, however, the near surface information was marred with ground roll. The data was reprocessed to extract seismic refraction tomography model, which has a better resolution of the very near surface structure even within the loose sand. The result obtained from the tomography model showed accurate distribution of seismic velocity, and the structural geometry within the very near surface. These information were used to effect static correction on the reflection data that delineated the deeper structures with the subsurface. A combination of the two techniques serves as better way to delineate the subsurface structure both at depth and in the very near surface.