In the central Andes, the Nazca plate displays large along strike variations in dip with a near horizontal subduction angle between 28 and 32◦S referred to the Pampean flat slab segment. The upper plate above the Pampean flat slab has high rates of crustal seismicity and active basement cored uplifts. The SIEMBRA experiment, a 43-broad-band-seismic-station array was deployed to better ch…