A numerical model for the simulation of the seismic cycle in dip-slip environments: Examples from Italy.
Albano M., Barba S., Bignami C., Doglioni C., Carminati E., Saroli M., Moro M., Stramondo S., Samsonov S.
IV - Geofisica e fisica dell'ambiente
GSSI Ex ISEF - Aula D - Giovedì 26 h 09:00 - 12:30
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According to the concept of the seismic cycle, earthquakes result from the strain accumulation over a variable decade to millennial period, $i.e.$, the interseismic stage, followed by a sudden stress release, $i.e.$, the coseismic stage, eventually evolving in the postseismic stage. Common analytical and numerical approaches simulate interseismic, coseismic and postseismic stages independently. Often, coseismic models constrain the slip of single or multiple planar sources to fit the available geodetic and InSAR measurements to reproduce fault geometry, slip and regional deformation, regardless of the origin of the interseismic forces. We developed a numerical model linking the ongoing interseismic viscous deformation at depth with the coseismic brittle episodic behavior of the upper crust. Our model assumes a brittle upper crust where the fault is locked, and a ductile lower crust, where the fault is steadily shearing. This approach is developed to model typical extensional and compressional earthquakes in Italy including the forces acting during the interseismic period, $i.e.$, the lithostatic load and the horizontal stress field. The results of our analysis, compared with the available geodetic and InSAR data, show that the proposed numerical model can reproduce the seismic cycle associated with the investigated events.