Application of seismic refraction tomography for subsurface imaging in central northern Nigeria.

Abstract

Seismic refraction tomography involves the measurement of the travel times of seismic refracted raypaths in order to define an image of seismic velocity in the intervening ground. This technique was used to estimate the depth to the fresh basement, estimate thickness of the weathered basement and to determine the subsurface lithology within the Basawa area of Zaria, which lies within the basement complex of northern Nigeria. Results of this study show that the thickness of the overburden within the survey area is about 10.05m which is also the depth to the weathered basement. The thickness of the weathered basement is about 7.04m. That is, the depth to the fresh basement is about 17.09m. The lithology analysis revealed that the top soil is made up of laterite and silty clay. The main aquifer is made up of weathered basement, pebbles and gravels, while the fresh basement is composed of granite, and quarzites occurring with gneisses.

Keywords: Seismic refraction, tomography and Central Northern Nigeria.

Nigerian Journal of Physics Vol. 19 (2) 2007: pp. 247-252