Good practice report: new developments in physics- and statistics-based earthquake forecasting

ETAS is currently the most widely accepted state-of-the-art when it comes to time-dependent earthquake forecasting. This model is based on a few simple assumptions and well-established empirical principles about earthquakes’ triggering behaviour. In ETAS, earthquakes can either be “background” events, or “triggered” events, and all of them can trigger cascades of aftershocks, following triggering laws, such as the Omori-Utsu law for the temporal distribution of aftershocks or the Gutenberg-Richter law for the frequency distribution of earthquake magnitudes. While it has been around for many years, ETAS hits a sweet spot between simplicity and accuracy, which makes it difficult for newer models to establish themselves as the new state-of-the-art.