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.