INVESTIGATION OF SUBSURFACE GEOLOGY IN THE TANO BASIN OF GHANA USING SEISMIC REFRACTION METHOD

2D seismic refraction data, from seven traverse lines, were used to investigate subsurface geology in the Appollonian Formation of the onshore Tano Basin of Ghana. Tano Basin is one of the four basins of Ghana and the most important one when it comes to oil potential of Ghana. The survey covered approximately a total area of about 113,000 m2. With the exception of one traverse line which had the length of 60 m, each of the remaining traverse lines had a length of 120m. The results from the data analysis indicated that, the surveyed area is underlain by three geological units although results from two traverse lines revealed two geological units. The P-wave velocity of the first layer ranges between 335.00 - 468.00 m/s and the average velocity of 391.57 m/s. It has a thickness range of 5.0 – 27.5 m with an average thickness of 16.25 m. The layer is interpreted as a weathered layer and consist of soil and dry loose sand which might be formed as beach deposit. The second layer has P-wave velocity range of 590.00 – 1133.00 m/s and the average velocity of 881.71 m/s. The layer thickness ranges between 14.5 – 31.0 m and the average of 25.80 m. The layer may consist of unconsolidated water- saturated sand and clay. The last layer detected by this survey has P- wave velocity range of 1068.00 – 2724.00 m/s and the average of 2074.20 m/s. The layer is interpreted as the bedrock underlining the surveyed area. The layer may consist of gravel, sandstone and limestone.

Anahtar Kelimeler:

Ghana, Tano Basin, Appollonian Formation, Seismic Refraction, Subsurface Geology.

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