Tanzania - Sustainable Use of Geothermal Energy - Structural- and InSAR analyses for a geothermal exploration programme in Northern Tanzania, based on remote sensing
Report of the project:
- Tansania - Nachhaltige Nutzung von geothermischer Energie
- Tanzania - Sustainable Use of Geothermal Energy
Within the bilateral project “Promoting the Development of Geothermal Energy, Tanzania” between BGR and Tanzanian Partners, the scope of the work lies upon the estimation of a possible potential for hydrothermal energy at Mount Meru.
By this time, available data, supporting a geothermal exploration programme in Northern Tanzania in a large scale is extremely limited. The area around Mt. Meru is hard to access due to steep terrain and dense vegetation cover. The combination of remote sensing methods can help to overcome this problem and figure out an area for further investigations:
Figure 1: The collapsed eastern flank of Mt. Meru. Perspective view into the crater with the central ash cone. Slope angle map derived from TSX WorldDEM projected over TSX DTM shaded relief. 1.5 X vertical exaggeration
Source: BGR
- The structural analysis is based on high- and medium resolution digital elevation models (DEM) and multispectral data. It improves the tectonic/geological understanding of the working area. Faults of different orientations, which can act as pathways for hydrothermal fluids can be detected as lineaments at the earth´s surface.
- Radar data cover huge areas and together with spaceborne Radar Interferometry (InSAR) processing supplies an excellent method for the detection of vertical ground movements in the range of a few millimetres per year. In combination with structural analyses, InSAR data can help to find locations of enhanced permeability for (hydrothermal) fluids and can also give hints for hydrothermal- and magmatic activities.
The structural analysis is the basis for the interpretation of the InSAR-processing results. The mapped lineaments represent faults, strongly connected to the youngest movements of the ongoing rifting of the Neogene rifts. Faults of WNW orientations dominate the Mt. Meru volcanic complex. Along these orientations, young hydrothermal alterations occur in the crater of the central ash cone as the youngest eruption centre. The InSAR analysis shows linear zones of subsidence at Mt. Meru, which follow the trends of existing faults and seem to be lineament-controlled.
Considering the combined results of these remote sensing studies, an area for further investigations can be suggested ESE of Mt. Meru.
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