A note on the L’Aquila earthquake of 6 April 2009: Permanent ground displacements obtained from strong-motion accelerograms

On 6 April 2009, 01:32 GMT, an Mw 6.3 earthquake hit the Abruzzi region of central Italy causing widespread damage in the City of L’Aquila and its nearby villages. The mainshock of this earthquake was recorded by 57 digital strong-motion instruments, four of which are located on the hanging wall of the Paganica Fault near L’Aquila. These stations are no more than 6 km from the epicentre. We use accelerometric data from these four stations to estimate permanent ground displacements caused by the mainshock. Our numerical results reveal south-east and downwards directed permanent co-seismic displacements which are in fair agreement with the outcomes of GPS and InSAR measurements reported in preliminary Istituto Nazionale di Geofisica e Vulcanologia (INGV) reports.