Application of Seismic Refraction Techniques in Geotechnical Evaluation for Sustainable Foundation in Parts of Bayelsa State, Nigeria

This study was carried out in Amassoama, Southern Ijaw Local Government Area of Bayelsa State and demonstrates the effectiveness of seismic refraction as a non-invasive, cost-efficient method for near-surface geotechnical characterization in the complex swampy terrain of Amassoama, Niger Delta. Utilizing an ABEM Terralog Mark 6 seismograph with 14 Hz geophones, we acquired four linear profiles measuring P- and S-wave travel times to depths of ~16 m. Velocity inversion of first-arrival data yielded detailed Vs (230–870 m/s) and Vp (420–1700 m/s) profiles, enabling derivation of key engineering parameters: elastic moduli, Poisson's ratio (0.26–0.35), and bearing capacity (Qa: 30–950 kPa). Results reveal a consistent velocity-depth relationship, with Vs increasing threefold from surface to bedrock, correlating with a 30-fold improvement in Qa. The method successfully identified weak surface soils (Qa < 50 kPa) requiring ground improvement, and competent strata at >10 m depth (Vs > 800 m/s, Qa > 280 kPa) suitable for pile foundations. These findings validate seismic refraction's capability to map soil-bedrock interfaces and quantify material competence in heterogeneous deltaic environments, providing critical data for foundation design while reducing reliance on extensive borehole investigations. The study establishes a framework for efficient geotechnical assessment in similar challenging terrains worldwide.