Effects of geological complexities on coseismic displacement: hints from 2D numerical modelling

By means of a 2D finite-element procedure, we tested how heterogeneities at the scale of seismogenic fault affect the displacement. We defined one or more slip distributions for two typical normal-faulting earthquakes in the Central Apennines, computed the displacement occurred within different structures including lateral heterogeneities, and compared the different displacement profiles to isolate the effect of the crustal structure. To understand at what magnitude the heterogeneities affect the observation significantly, we compared the predicted coseismic displacement with GPS and DInSAR data for the Colfiorito 1997 earthquake. We find that heterogeneities significantly affect the observable horizontal coseismic displacement for the larger magnitudes, whereas for smaller quakes, they affect horizontal displacement close to the fault trace only.