The
gravity modelin
g of the Eburru was conducted in an attempt to delineate
geolo
gical structures controllin
g he
geothermal system and estimate the
geothermal reservoir extent. A total of 375 data points were used and a Bou
guer density of 2.27
g/cm3 to
generate a complete Bou
guer anomaly map of the area. Gravity data were separated into re
gional and residual components to enhance the structural features from the sedimentary and basement rocks in the study area. The
gravity data were analyzed usin
g gradient interpretation techniques for ed
ge detection, such as horizontal derivative and an improved normalized horizontal tilt an
gle. For carryin
g out the three-dimensional (3-D) modelin
g, a volume of 12 × 13 km and 5 km deep was selected. The model was constrained usin
g the estimated densities of cuttin
gs obtained from the drilled wells. This study presents the interpretation results of various
gravity anomaly maps and 3-D inversion model. Interpretation of horizontal derivative and improved normalized horizontal tilt an
gle of
gravity data indicate the existence of hi
gh
gradient anomalies. The anomaly maps were used to identify several faults that compared well with the mapped faults. The 3-D model revealed a dense body interpreted as the
geothermal reservoir with a volume of about 3.0 km3 and an avera
ge block density value of 2.45
g/cm3 . The dense body which is a fractured zone overlies a hi
gh density body likely to be the heat source responsible for heatin
g the reservoir. There appears to be a close relationship between the faults system and the
geothermal reservoir. These faults serve as fluid pathways from deeper parts to shallow re
gions. The results obtained from this study will lead to an improved understandin
g of the
geothermal system in the study area and aid the future
geothermal exploration of the field.