Caldera collapse and tectonics along the Main Ethiopian Rift: reviewing possible relationships

Abstract

The Main Ethiopian Rift (MER) represents an area where volcanism and tectonics interact to create closely linked volcano-tectonic features. This linkage is paramount in the axial portion of the rift, where magmatic segments localize several large peralkaline eruptive centres. Many of them evolved into caldera collapse (the best preserved of which are younger than <1 Ma) generating large ignimbrites and registering the interaction between magmatism and tectonics along the MER. In this work we review the structure of the main collapsed calderas along the axial portion of the MER, to summarize the relationships between volcanism and tectonics proposed in the literature explaining their structural evolution. By doing this, we infer that tectonics had a strong influence in controlling the elongation of the majority of examined calderas. This control was induced by reactivation of inherited crustal fabrics or by stretching of the magma reservoirs under the MER regional stress field.

Unraveling the Geothermal Potential of Corbetti Caldera Using Integrated Geophysical Methods, Central Main Ethiopian Rift

“…Figure 4: (A) Topographic maps, (B) Free-Air anomaly of Corbetti Caldera and its surroundingsThe free air effect is simply the gravitational change caused by a difference in elevation between stations. The free air anomaly map (Fig 4B)shows a strong correlation with local topographic map (Fig 4A), this shows the reliability of the gravity data collected on the area[59][60][61]. The Free-air anomaly map shows its maximum, about 45mgal and its minimum -2mgal in the study area of interest, i.e., the Chebbi and Urji volcanoes are the highest elevated areas of Corbetti caldera which is about 2100m.s.l and the volcanoes are associated with maximum Free-air anomaly which is about 45mgal.…”

Unraveling the Geothermal Potential of Corbetti Caldera using Integrated Geophysical Methods, Central Main Ethiopian Rift

“…The Corbetti caldera having elevated volcanic complexes such as Chebbi and Urji is a nested caldera within the Awassa caldera (Hutchison et al, 2016;Maestrelli et al, 2021). The region as it is shown in the topographic map ( which implies an addition of material with higher mass density than that of surrounding rocks (Gottsmann et al, 2020;Lavayssière et al, 2019;Mickus et al, 2007).…”

Large-to Local-Scale Control of Pre-Existing Structures on Continental Rifting: Examples From the Main Ethiopian Rift, East Africa

“…Overall, the Ririba example supports that major, lithospheric-scale inherited structures may represent zones of crustal weakness that magma can exploit during its ascent, controlling the volcanic spatial and temporal evolution, volcanic morphology, magma volume, and eruptive dynamics (e.g., Le Corvec et al, 2013;Wadge et al, 2016). In a recent compilation, Maestrelli et al (2021) suggested that at least some calderas in the MER (e.g., Fantale, Kone, Gedemsa and Corbetti) may have experienced a tectonic control exerted by pre-existing faults reactivated during the collapse (i.e., faultcontrolled caldera rim; Figure 11). Furthermore, Acocella et al (2002) hypothesized a control exerted by inherited structures, reactivated during rift extension, on the localization for Fantale, Kone and Gedemsa calderas.…”