Postseismic Deformation of the 2009 L’Aquila Earthquake (M6.3) Surface Rupture Measured Using Repeat Terrestrial Laser Scanning

We have conducted an innovative repeat terrestrial laser scan survey at four sites on the NW-SE striking surface rupture of the 2009 LAquila earthquake (M6.3). Between 8 126 days after the earthquake we repeatedly laser scanned the surface of four road sections cross-cut and vertically offset by the surface rupture. We registered the laser scan data from each site into a footwall static reference frame and interpolated the data to form representative road surfaces. We were able to model rupture afterslip and associated near-field postseismic deformation at each site in the immediate hangingwall with millimetre to sub-centimetre precision. We identify that the magnitude of postseismic deformation observed at site PAG towards the centre of the rupture persists sites SP and EP towards the SW tip of the rupture. The postseismic deformation observed at site TM, towards the NW tip of the rupture however, shows a decrease in postseismic deformation from that seen at PAG. We correlate the large magnitudes of postseismic deformation at sites on the SW end of the rupture to an increased coseismic slip deficit in this part of the fault zone, thought to be the driving mechanism of afterslip and near-field postseismic deformation. Conversely, the lack of significant postseismic deformation observed along the NW section of the rupture at site TM is thought to be controlled by the lack of a significant coseismic slip deficit within this part of the fault zone.