Simple smoothed seismicity earthquake forecasts for Italy

Several earthquake forecast experiments in Italy have been initiated within the European testing center of the global Collaboratory for the Study of Earthquake Predictability. In preparation for these experiments, we developed space-rate-magnitude forecasts based on a simple model that incorporates the spatial clustering of the seismicity. This model, which we call the simple smoothed seismicity model (TripleS), has a minimal number of free parameters and is based on very few assumptions; therefore, it can be considered as a model of «least information» with which others can be compared. The fundamental TripleS parameter controls the spatial extent of the smoothing, and we selected its value based on an optimization procedure that was applied to retrospective forecast experiments. In this report, we present the motivation for developing TripleS, and describe the construction of forecasts for Italian seismicity. We also discuss the research questions that remain to be answered with respect to TripleS, and more generally, the smoothed seismicity approach to earthquake forecasting.