Volume 62, Issue 342, September - December 2026

Integration of seismic refraction, electrical resistivity and geotechnics in characterizing near surface soil: a case study of Niger Delta Region

Okezie Uchegbulam^1♦, Elijah Ovie Izeze²

¹Department of Applied Geophysics, Federal University of Petroleum Resources, Effurun, Nigeria
²Department of Geology, Federal University of Petroleum Resources, Effurun, Nigeria

^♦Corresponding Author
Okezie Uchegbulam, Department of Applied Geophysics, Federal University of Petroleum Resources, Effurun, Nigeria.

ABSTRACT

Water saturated near surface soil of Niger Delta’s sedimentary terrain was characterized by using seismic refraction, electrical resistivity and geotechnical data due to topographic complexities that may cause geotechnical instabilities. Seismic refraction survey occupied two traverses, the two profiles revealed a 3-layered subsurface structure having different mechanical properties with compressional wave p V and shear wave s V velocities that increased with depth. Compressional wave increased from 270.87m/s in the first layer to 921.18m/s in the third layer, while shear wave increased from 130.12 m/s in the first layer to 442.52 m/s in the third layer. The electrical resistivity  result delineated five geo-electric layers with HKQ curve of resistivity ρ1 > ρ2 < ρ3 > ρ4 > ρ5 indicating loose dry fine sand with resistivity  3684.7m at the depth of about 0 – 7m beneath the surface and saturated medium coarse sand of resistivity  442.52m at the depth of 38m and beyond. Geotechnical parameters derived from seismic sections shows that Young’s modulus increased from 82.29MPa in the first layer to 951.71MPa in the third layer. Likewise, shear modulus recorded an increment of 30.48MPa in the first layer to 352.48MPa in the third layer. Bulk modulus also increased from 101.59MPa in the first layer to 1174.95MPa in the third layer. Poisson’s ratio and density are about 0.35 and 1800kg/m3 respectively in the three layers because near surface soil of the area is composed of lateritic soil with high percentage of sand. The area has porosity of 0.31 indicating sand materials. The increment of the wave velocities and elastic constants with depth is an indication of more consolidation of materials beneath the surface. The implication of the results is that foundation for superstructures should get to the second or third layer at depth (  10m) beneath the surface where earth materials are stiffer for structural stability.

Keywords: Near Surface; Refraction; Resistivity; Seismic; Stiffness

Discovery, 2026, 62, e30d3333

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Published: 12 October 2026