Subsurface Mass Rippability Assessment in Basement Environment Using Seismic Refraction Survey

Abstract

A geophysical investigation was carried out in Kong, northern Côte d’Ivoire, to characterize the subsurface formations as part of a drinking water supply project. The study aimed to determine the seismic signatures of the non-rippable layers and their depths to guarantee the stability of the Kong water reservoir. Based on the analysis of Vp velocity distribution, the subsoil in the study area is structured into rippable (300 - 1500 m/s), marginal (1500 - 2000 m/s) and non-rippable (>2000 m/s) zones with varying thicknesses. Correlation with core drilling results reveals that the rippable zones, located between 5 and 9 m depth, are associated with the superficial overburden and weathering products (clays and clayey sands), while the non-rippable zones correspond to the very dense granitic basement, located between 5 and 11 m depth according to 2D geoseismic sections.