Magnetic anomaly patterns and volcano-tectonic features associated with geothermal prospect areas in the Ziway-Shala Lakes basin, Central Main Ethiopian Rift

Stratigraphy and eruptive history of Gedemsa caldera volcano, Central Main Ethiopian Rift

“…Previous studies also suggest that the underlying mafic magma is prohibited from reaching the surface due to the upper silicic layer acting as a density barrier (Peccerillo et al, 2003). A similar sequence is observed in borehole data collected from the caldera floor that goes as deep as 200 meters below the ground surface (Kebede, 1988). The results show the alternating sequence of mafic and rhyolitic products punctuated by pumiceous ignimbrites until the pyroclastic deposits completely dominate (Fig.…”

“…Both boreholes encountered alluvium sediments, pumice deposits, rhyolites, basalts, and pumiceous ignimbrites (Fig. 2C; Kebede, 1988).…”

Subsurface structural control of geothermal resources in a magmatic rift: gravity and magnetic study of the Tulu Moye geothermal prospect, Main Ethiopian Rift

“…The residual gravity anomaly map (Figure 6) and derivative maps (Figures 5, 6) revealed a spatially large circular maximum with overlapping smaller elliptical to circular-shaped maxima. The large circular region (Figures 3, 5, 6) could be evidence for the single large caldera model (Fontijn et al, 2018;Varet and Birba, 2018;Guծbrandsson et al, 2020) whereas, overlapping smaller elliptical-circular positive gravity anomalies could reveal a nested caldera system (Kebede, 2021). This observation can be interpreted as that the TMGP consists of an older large caldera, about 25 km in diameter followed by several smaller, younger calderas (Bora, Bericha, and TM) (Figure 12).…”

“…This observation can be interpreted as that the TMGP consists of an older large caldera, about 25 km in diameter followed by several smaller, younger calderas (Bora, Bericha, and TM) (Figure 12). Caldera rims are not visible in many locations due to modification by erosion and post-caldera volcano-tectonic activities associated with the Quaternary-Recent NNE-SSW trending structures related to the WFB and the cross-rift (NW-SE) structures (Figures 5-7) (Kebede, 2021).…”