Application of Seismic Refraction Tomography to Determine the Subsurface Lithology Within Fupre Health Center

A seismic refraction survey was conducted at the Federal University of Petroleum Resources Effurun(FUPRE) health center to investigate the subsurface lithology for potential construction purposes and further hydrological studies. The study employed six shots, including forward and backward configurations, across a 100-meter geophone spread with 4-meter spacing using a 24-geophone setup.Data acquisition and processing involved removing unwanted signals, followed by the interpretation of field and processed travel time curves to delineate subsurface layers and assess their physical properties. The results revealed three distinct subsurface layers. The first layer, approximately 8 meters thick with an average P-wave velocity of 232.04 m/s, comprises loose, unconsolidated materials such as sand, clayey soil, or topsoil. These materials are highly porous and poorly compacted, making them unsuitable for bearing heavy structural loads without proper reinforcement.The second layer, with a thickness of approximately 16 meters and velocities ranging from 320 to 410 m/s, represents more compacted or slightly consolidated sediments, likely sandy clay or silty sand. This layer serves as a transitional zone with moderate compaction and potential water saturation. The third layer, with velocities exceeding 800 m/s, could not be fully resolved in terms of thickness due to the shallow depth of investigation. However, its high velocity indicates compacted coarse sandstone or weathered rock, which is competent and stable enough for structural foundations.Further geotechnical investigations, including borehole drilling and complementary geophysical methods, are recommended to confirm the engineering properties of these layers, particularly the third, to ensure safe and reliable construction near the health center.