Partitioned postseismic deformation associated with the 2009 Mw 6.3 L'Aquila earthquake surface rupture measured using a terrestrial laser scanner

Abstract

Using 3D terrestrial laser scan (TLS) technology, we have recorded postseismic deformation on and adjacent to the surface rupture formed during the 6th April 2009 L'Aquila normal faulting earthquake (Mw 6.3). Using surface modeling techniques and repeated surveys 8-124 days after the earthquake, we have produced a 4D dataset of postseismic deformation across a 3 × 65 m area at high horizontal spatial resolution. We detected millimetre-scale movements partitioned between discrete surface rupture slip and development of a hangingwall syncline over 10's of meters. We interpret the results as the signal of shallow afterslip in the fault zone. We find 52% of the total postseismic hangingwall vertical motion occurs as deformation within 30 m of the surface rupture. The total postseismic vertical motions are approximately 50% that of the coseismic. We highlight the importance of quantifying partitioned postseismic contributions when applying empirical slip-magnitude datasets to infer palaeoearthquake magnitudes. Copyright © 2010 by the American Geophysical Union.