The gravity structure of Eberru, Kenya

Abstract

Gravity data show that the Eburru area has a complex gravity structure. The results show a N-S axial high along a graben caused by dense intrusives along N-S fault zones and at major structural intersections within the area. Low frequency filtering delineates a major NE-SW negative anomaly modelled as a basin structure, at whose intersection with the N-S graben occurs the Eburru caldera. Within it, one well has been drilled with a 2.5 MWe production capacity. High frequency anomalies are related to vertical intrusives at shallow depths, occurring at fault junctions. Analysis of these anomalies has led to a proper definition of a NW-SE structural and resistivity discontinuity, dividing the study area into two regions. This has also led to the confinement of the Eburru caldera boundaries. Fluid feed for the geothermal system is along vertical conduits and the heat coming from narrow intrusive bodies at fault junctions.