SIGMA: a software tool to simulate non-stationary ground motions for engineering applications

The selection of the input ground motion is becoming more and more important in the framework of earthquake engineering. Simulated ground motion time series can be a valid alternative to natural ground motions, which can be scarce for certain combinations of earthquake scenario and site conditions, especially for large, infrequent earthquakes. The simulated records can be used for applications in nonlinear dynamic analyses of civil structures. This work presents a new Matlab-based software tool that allows to generate a chosen number of simulated ground motions given few input parameters, namely Magnitude, Distance, VS,30 and Style of Faulting. The time series are simulated with an up-to-date non-stationary stochastic model which was calibrated using the empirical ground motion model (GMM) based on the latest version of the Italian Strong Motion database ITACA. The simulated accelerograms show a good match with the GMM in terms of response and Fourier spectra, PGA and Arias Intensity