Prospective CSEP evaluation of 1-Day, 3-month, and 5-Yr earthquake forecasts for Italy

In 2009, the global Collaboratory for the Study of Earthquake Predictability (CSEP) launched three experiments to forecast the distribution of earthquakes in Italy in the subsequent 5 yrs. CSEP solicited forecasts for seismicity tomorrow, in the next three months, and for the entire 5 yrs. In those 5 yrs, the Istituto Nazionale di Geofisica e Vulcanologia (INGV) recorded 83 target earthquakes with local magnitude 3:95 =M <4:95, and 14 larger shocks. The results show that 1-day forecasts are consistent with the number and magnitudes of the target earthquakes, and one version of the epidemic-type aftershock sequence (ETAS) model is also consistent with the spatial distribution; ensemble forecasts, which we created for the 1-day experiment, are consistent with the number, locations, and magnitudes of the target earthquakes, and they perform as well as the best model; none of the 3-month time-independent models produce consistent forecasts; the best 5-yr models account for the fault distribution and the historical seismicity; and 5-yr models based on instrumental seismicity and b-value spatial variation show poor forecasting performance.