GEOPHYSICAL CHARACTERIZATION OF THE EBURRU GEOTHERMAL SYSTEM IN KENYA

Geothermal exploration typically focuses on the identification of the heat source and defining the plumbing system that allows fluid flow at depths of 1-5 km where production of geothermal energy is feasible. The faults and fracture systems that make up the plumbing systems for hydrothermal fluids are often offset from their source and may be entirely hidden beneath basin fill or volcanic flows. Thus, a variety of different geophysical methods are used to detect the fracture zones and heat sources, including electrical, electromagnetic, seismic and potential field techniques, with limited success.

To improve on characterizing structures within geothermal systems we employ magnetotelluric (MT) and potential field data (gravity and magnetic) at the Eburru geothermal field of Kenya. Geothermal structures (reservoir, cap rock and heat source) are often concealed beneath the surface. A variety of gravity and magnetic maps (residual and derivatives) and two- and three-dimensional modeling of the MT and potential fields data will be used to define the electrical resistivity, density and magnetic susceptibility distribution within the Eburru geothermal field. The resultant models will then be interpreted as potential targets of any geothermal sources.