Seismic images of magmatic rifting beneath the western branch of the East African rift

摘要: [1] We have performed a tomographic study using joint data set that includes local and teleseismic events, recorded by temporary network in the western branch of East African rift system. From travel time residuals, we derive three-dimensional model seismic P-wave velocity anomalies for crust upper mantle down to depth 80 km. Particular attention is paid verification inversion results various resolution tests. The show eastern shoulder characterized relatively high velocities. Lower velocities are obtained beneath entire length valley Rwenzori Mountains. A prominent feature observed north-east mountain range: here detected vertically oriented, cylindrical low-velocity anomaly with maximum amplitudes middle lithosphere. We suggest this indicates reservoirs molten material related ongoing rifting process within segment rift. Just above anomaly, at depths between 5 16 km, earthquake swarms exist. reduction used provide constraints on possible melt content temperature uppermost mantle. 3–5% P-velocity decrease can be explained fraction up 2%–3.3% or alternatively increase least 248 376 K even higher-temperature if lower ambient temperatures reference assumed. Probably, two effects act combination.