Radon and Soil Gas Surveys in Paka Geothermal Propect, Kenya

Abstract

Radon and soil gas surveys involved measuring of carbon dioxide gas using an Orsat apparatus and radon gas using an Emanometer. The Paka geothermal prospect has sparse groundwater boreholes and almost non existent hot springs. Radon soil gas was conducted as part of the sampling programme in Paka. The radon soil gas were conducted to determine the greatest extend to which high radon counts could be determined. The lowest radon counts from the radon surveys were observed to the south, west, the northern and eastern parts of the Paka geothermal prospect. Most of these parts were covered by alluvial deposits. This restricts the paths for radon as it ascends to the surface and thus lowers the counts. In the central parts of Paka Volcano, high radon counts were encountered in the vicinity of the summit and areas of high fumarolic activity. This could be associated with possibly a highly fractured area and high heat flux. High carbon dioxide gas (CO2) concentrations in the soil gas was observed close to central parts of Paka on the summit volcano. In an east-west trend on the western of the summit volcano, the amount of CO2 in soil gas values increased. In a north-south trend along the summit volcano, the amount of CO2 in soil gas values increased. In a north south pattern on the summit volcano, high CO2 concentrations were observed. This could be associated with proximity to a magma source and deep seated faults.