Subsurface characterization of the Pwalugu multi-purpose dam site using shallow seismic refraction technique

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MAY, 2016
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2D shallow seismic refraction survey technique has been applied at the proposed Pwalugu dam site to find out how suitable the subsurface is, for the engineering project. The geology of the project site is made up of the Upper Voltaian which is mainly characterised by sandstone. Ten traverses having different lengths oriented across the strike with geophone separation of either 4 or 5 m were conducted at the site. Seismic data were collected using 10 Hz electromagnetic geophones with the ABEM Terraloc Mk.6, a 24 channel recording system. The data was processed with the ReflexW software into 2D velocity depth models unveiling three acoustic layers. P-wave velocities averaging up to1400,3200 and 5300m/s were recorded for the first, second and third layers respectively. The 2D velocity depth models together with geologic information from the study area reveal that the overburden is made up of alluvium, the intermediate layer is made up of compacted alluvial deposits whilst the third layer suggest the massive sandstone bed. The seismic method delineated the bedrock at depths greater than 20 m at thevarious locations.
A thesis submitted to the Department of Physics, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the degree of Master of Philosophy.