A gravity survey of the Longonot-Suswa area
Abstract
The area of study comprises a part of the Rift Valley which has geothermal
potential. The gravity prospecting method was used in the project to
investigate the anomalies occur in the area. Qualitative and quantitative
interpretations were attempted and conclusions drawn from the findings.
A gravity survey was conducted to "fill-in" the unsurveyed
sectors. After applying the necessary corrections to the field data, digital
filtering was applied. The filtering helped to remove or significantly
attenuate the geologic noise. Bouguer anomaly maps of the area were then
drawn. The filtered data reliably indicate geological structures of
interest. The Bouguer gravity values range from-208 to -156mgele with the
minimum peak occur directly above the Longonot volcano. Other anomalies
occur at Buni and the HeIle Gate in the Ol'Njorowa gorge. The relationship
between location of the gravity anomalies and the topographic features
of the area is clearly noticeable.
The quantitative interpretation involved fitting theoretical
three-dimensional models to the observed data along profiles. The choice of
three-dimensional models was dictated by the shape of the anomalies to be
interpreted. The anomalies were interpreted in terms of intrusions of
several bodies. A density of 2.0 gcm-3 was used for the intrusive
bodies. The geometries of these bodies were also determined. Two of the most
striking feature e which were interpreted are the "bum" and the "crater"
dykes. The study of the anomalies indicated that the major gravity disturbances
were caused by the rifting and the subsequent tectonic activities. The
agreement between the final geophysical model with the characteristics of the
known geology shows that the model is reasonable.
Citation
M.Sc. (Geology) Thesis 1993Sponsorhip
University of NairobiPublisher
Department of Geology, University of Nairobi
Description
Master of Science Thesis