A double-branching model applied to long-term forecasting of Italian seismicity (ML≥5.0) within the CSEP project

Abstract

The purpose of this work is to apply the Double Branching Model to forecasting of moderate-large Italian seismicity in the CSEP experiment. The CSEP project is directed to the statistical evaluation and comparison of some forecasting models both at global and at regional scales. The proposed model is time-dependent, since it assumes that each earthquake can generate or is correlated to other earthquakes, through physical mechanisms acting at different spatio-temporal scales. Specifically it consists of an application of two branching processes, in which any earthquake can trigger a family of later events on different space-time scales. In a recent paper (Lombardi and Marzocchi, 2009) we have applied the model to a declustered historical database, collecting the strong Italian seismicity of last centuries. This catalog allowed us to describe only the long-term time evolution of moderate-strong seismicity. Here we apply the model to a new database allowing us to describe both short-term clustering and long-term features at the same time. Since the model is able to produce forecasting calculations of future seismicity, we provide some probability maps of occurrence of next events for different temporal windows.