Comprehensive seismic refraction analysis and 2-D geological modeling in Ini Local Government Area, Akwa Ibom State, Nigeria

Abstract

Seismic refraction methods are vital in geophysical investigations to reveal subsurface geological structures. This study focuses on the Ini Local Government Area, Akwa Ibom State, Nigeria, analyzing geological features beneath the surface, with emphasis on seismic velocities and layer thicknesses. The primary aim was to determine subsurface composition, identify geological disruptions, and develop 2-D subsurface models using seismic refraction data. Data were collected from forty locations using a Geometric ES 3000 12-Channel Seismograph, a Vulcan Sledge Hammer as the energy source, and geophones as detectors. The data were processed into Two-Way Time (TWT) graphs, and models were generated using strata modeling software. Three primary layers were identified: Layer 1 (topsoil) with lower seismic velocities (209-500m/s) and shallow depths (1-3m), Layer 2 (consolidated subsoil) with higher velocities (221-1210m/s) and greater depths (4-9m), and Layer 3 (bedrock) with the highest velocities (510-1700m/s) and depths (4.5-14.5m). Variations in seismic velocities and thicknesses highlighted geological instabilities. The VP/VS and Poisson’s ratios provided insights into lithological variations. 2-D sections showed lateral variations and models revealed disruptions like faults. The study delineated three seismic layers, highlighting areas with suitable and unsuitable conditions for construction. This research’s novelty lies in integrating seismic refraction data with advanced 2-D modeling, offering a comprehensive subsurface analysis crucial for construction planning and geological hazard assessment in Ini Local Government Area (LGA).