Microearthquake Survey at the Buranga Geothermal Prospect, Western Uganda

Abstract

The BGR supports the Government of Uganda in the geoscientific investigations of the Buranga geother-mal prospect since 2004. The objective of the project is to raise the knowledge about Buranga to a level (pre-feasibility status) that can be the base for plan-ning of exploration wells.
Geochemical findings, which have been achieved in the framework of the joint project, proofed the exis-tence of a magmatic body that in all probability serves as the heat source of the hot springs. Hence the task of active ground geophysics was detecting and delineating this magmatic intrusion. The known high seismicity (about 300 local earthquakes per month) suggested that Buranga provides excellent pre-conditions to apply seismology.
From May 2005 to August 2006 up to 15 seismologi-cal stations were deployed to record local earth-quakes in the Buranga region. The tomography of the seismic data is expected to yield two results:
-- delineation of the magmatic intrusion at depth and
-- delineation of the active faults/fault systems by an exact localization of the hypocenters.

First results will be presented here. They will be reinforced and better elaborated when all the data will be included. Low velocity anomalies, supposed to represent the magmatic intrusive bodies, are shown in horizontal and vertical sections and are constituted at depths levels even below 15km.