Shear-wave velocity profile and seismic input derived from ambient vibration array measurements: the case study of downtown L'Aquila

Downtown L'Aquila suffered severe damage (VIII-IX EMS98 intensity) during the 2009 April 6 M-w 6.3 earthquake. The city is settled on a top flat hill, with a shear-wave velocity profile characterized by a reversal of velocity at a depth of the order of 50-100 m, corresponding to the contact between calcareous breccia and lacustrine deposits. In the southern sector of downtown, a thin unit of superficial red soils causes a further shallow impedance contrast that may have influenced the damage distribution during the 2009 earthquake.