title: Gravity-driven postseismic deformation following the Mw 6.3 2009 L'Aquila (Italy) earthquake.
abstract: The present work focuses on the postseismic deformation observed in the region of L'Aquila (central Italy) following the Mw 6.3 earthquake that occurred on April 6, 2009. A new, 16-month-long dataset of COSMO-SkyMed SAR images was analysed using the Persistent Scatterer Pairs interferometric technique. The analysis revealed the existence of postseismic ground subsidence in the mountainous rocky area of Mt Ocre ridge, contiguous to the sedimentary plain that experienced coseismic subsidence. The postseismic subsidence was characterized by displacements of 10 to 35 mm along the SAR line of sight. In the Mt Ocre ridge, widespread morphological elements associated with gravitational spreading have been previously mapped. We tested the hypothesis that the postseismic subsidence of the Mt Ocre ridge compensates the loss of equilibrium induced by the nearby coseismic subsidence. Therefore, we simulated the coseismic and postseismic displacement fields via the finite element method. We included the gravitational load and fault slip and accounted for the geometrical and rheological characteristics of the area. We found that the elastoplastic behaviour of the material under gravitational loading best explains the observed postseismic displacement. These findings emphasize the role of gravity in the postseismic processes at the fault scale.
authors.affiliation: Istituto Nazionale di Geofsica e Vulcanologia, Rome, 00143, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Albano
authors.affiliation: National Institute of Geophysics and Volcanology, National Earthquake Center, Rome, 00143, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Barba
authors.affiliation: University of Cassino and Southern Lazio, Department of Civil and Mechanical Engineering, Cassino, 03043, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Saroli
authors.affiliation: National Institute of Geophysics and Volcanology, National Earthquake Center, Rome, 00143, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Moro
authors.affiliation: e-GEOS, an Italian Space Agency (ASI) and Telespazio Company, Rome, 00156, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Malvarosa
authors.affiliation: e-GEOS, an Italian Space Agency (ASI) and Telespazio Company, Rome, 00156, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Costantini
authors.affiliation: National Institute of Geophysics and Volcanology, National Earthquake Center, Rome, 00143, Italy.
authors.forename: Christian
authors.initials: C
authors.lastname: Bignami
authors.affiliation: National Institute of Geophysics and Volcanology, National Earthquake Center, Rome, 00143, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Stramondo