Seismicity and Crustal Structure of the Southern Main Ethiopian Rift: New Evidence From Lake Abaya

The Main Ethiopian Rift (MER) has developed during the 18 Ma-Recent separation of Nubian and Somalian plates. Extension in its central northern sectors is associated with seismic activity active magma intrusion, primarily within rift, where shallow (5 km) seismicity along magmatic centers commonly caused by fluid flow through open fractures hydrothermal systems. However, extent to which similar rifting persists into southern MER unknown. Using data from a temporary network five seismograph stations, we analyze patterns crustal structure Abaya region MER. Magnitudes range 0.9 4.0; earthquake depths are 0–30 km. ratios 1.69, estimated Wadati diagram analysis, corroborate bulk-crustal determined via teleseismic P-to-S receiver function H- stacking reveal relative lack mafic intrusion compared rift north. There clear association western border fault system everywhere our study area, but near Duguna volcano, implying shallowed geothermal gradient valley silicic magmatism. This part thus interpreted best as young that locally impacts not yet significantly modified continental composition rift-axial rifting.