| Summary: | Tese de doutoramento, Ciências Geofísicas e da Geoinformação (Geofísica), Universidade de Lisboa, Faculdade de Ciências, 2017 Twelve combined wide-angle refraction and coincident multi-channel seismic profiles were acquired in the Recˆoncavo, Tucano, Jequitinhonha, Camamú-Almada, Jacuípe, and Sergipe-Alagoas basins, NE Brazil, during the SALSA experiment in 2014. Profiles SL11 (170 km long) and SL12 (180 km long) image the Jequitinhonha basin perpendicularly to the coast, with 15 and 11 four-channel ocean-bottom seismometers, respectively. Forward modelling, combined with pre-stack depth migration to increase the horizontal resolution of the models, resulted in P-wave velocity models that allow the characterisation of the crustal structure and lithospheric mantle of the Jequitinhonha and Camamu-Almada basins. The models are also consistent with the shipboard and satellite gravity anomaly observations. On both profiles, the sedimentary layers reach a thickness of, at least, 3:3 km in the distal basin. The thickness of the sediments increases gradually towards the coast, up to 4:1 km on profile SL11 and up to 6:2 km on SL12. Eight sedimentary mega-sequences are identified and modelled from both OBS and MCS data. Their P-wave seismic propagation velocities increase gradually inside the sedimentary column, although with a slight decrease towards the distal basin, specially on the shallowest layers. Acoustic propagation velocities in the sediments range from 1:8 km=s to 5:2 km=s. These values are confirmed by the RMO analysis of PSDM images. The basement structure has five layers: upper crust, middle crust, lower crust, anomalous velocity zone, and lithospheric mantle. The upper crust has a thickness of 1:0-2:0 km on the distal basin, increasing to 3:7 km on SL11 and 2:9 km on SL12 on the continental slope, with velocities at the top and bottom of the western end from 5:2 km=s to 5:3 km=s that, on profile SL11, decrease to 4:7 km=s and 5:0 km=s at the eastern end. On profile SL11, the middle crust thins from 6:5 km ...
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