Fluid migration inducing ground deformation before the 2009 L'Aquila earthquake
Abstract
We investigated the 2009 L'Aquila earthquake (M=6.3) seismic cycle analysing the ground deformation inferred from multitemporal InSAR techniques. To such aim we processed a huge dataset composed by Radarsat 1, Envisat and Cosmo Skymed SAR (Synthetic Aperture Radar) images spanning six years before and sixteen months after the main shock. The results from multitemporal InSAR highlighted a subsidence, of about 5-10 mm, close to the epicentral area and starting about three years before the earthquake. Such subsiding areas are defined within two quaternary basins characterized by the presence of a water table. In such quaternary basins we observed an inversion of the deformation trend during the post-seismic phase starting about 10 months after the earthquake and reaching about 15-20 mm of uplift. Such a behaviour can be explained thanks to the dilatancy theory applied to the carbonatic hydrostructures surrounding the L'Aquila basin. Stemming from this theory we can assume that the evolution phases of the diltancy, corresponding to the increase of the fracturing during the pre-seismic phase, induce changes on the water table of the carbonatic hydrostructure. These changes have effects on the multi-stratigraphic aquifer of the two quaternary basins, which are feed by the carbonatic hydrostructures.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMNH21A1830M
- Keywords:
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- 4303 Hydrological;
- NATURAL HAZARDSDE: 4315 Monitoring;
- forecasting;
- prediction;
- NATURAL HAZARDSDE: 4317 Precursors;
- NATURAL HAZARDSDE: 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGY