Spectral element numerical simulation of the 2009 L'Aquila earthquake on a detailed reconstructed domain

In this paper, we simulate the earthquake that hit the city of L'Aquila on 2009 April 6 using SPEED (SPectral Elements in Elastodynamics with Discontinuous Galerkin), an open-source code able to simulate the propagation of seismic waves in complex 3-D domains. Our model includes an accurate 3-D reconstruction of the Quaternary deposits, according to the most up-to-date data obtained from the Microzonation studies in Central Italy and a detailed model of the topography incorporated using a newly developed tool. The sensitivity of our results with respect to different kinematic seismic sources is investigated. The results obtained are in good agreement with the recordings at the available seismic stations at epicentral distances within a range of 20 km. Finally, a blind source prediction scenario application shows that a reasonably good agreement between simulations and recordings can be obtained by simulating stochastic rupture realizations with basic input data. These results, although limited to nine simulated scenarios, demonstrate that it is possible to obtain a satisfactory reconstruction of a ground shaking scenario employing a stochastic source constrained on a limited amount of ex-ante information. A similar approach can be used to model future and past earthquakes for which little or no information is typically available, with potential relevant implications for seismic risk assessment.