dr. Nicola D'Agostino, Istituto Nazionale di Geofisica e Vulcanologia - Centro Nazionale Terremoti - ore 11.30 - aula 1G09 - Dipartimento di Fisica "Ettore Pancini", Complesso Universitario di Monte S.Angelo - Via Cintiia, Napoli.
ABSTRACT
In this seminar I will present recent results pointing out evidence of transient, hydrologically-related deformations observed with geodetic data in the Southern Apennines. GPS, hydrological, and GRACE (Gravity Recovery and Climate Experiment) observations in southern Apennines (Italy) have been used to highlight a previously unnoticed response of the solid Earth to hydrological processes. Transient patterns in GPS horizontal time series near to large karst aquifers are controlled by seasonal and interannual phases of groundwater recharge/discharge of karst aquifers, modulating the extensional ∼3 mm/yr strain within the tectonically active Apennines. We suggest that transient signals are produced, below the saturation level of the aquifers and above a poorly constrained depth in the shallow crust, by time-dependent opening of subvertical, fluid-filled, conductive fractures. We ascribe this process to the immature karstification and intense tectonic fracturing, favoring slow groundwater circulation, and to multiyear variations of the water table elevation, influenced by variable seasonal recharge.