Incorporating Foreshocks in an Epidemic-like Description of Seismic Occurrence in Italy

The Epidemic Type Aftershock Sequence (ETAS) model is a widely used tool for cluster analysis and forecasting, owing to its ability accurately predict aftershock occurrences. However, capacity explain the increase in seismic activity prior large earthquakes—known as foreshocks—has been called into question due inconsistencies between simulated experimental catalogs. To address this issue, we introduce generalization of ETAS model, Foreshock (ETAFS) model. This has shown describe seismicity Southern California. In study, demonstrate that ETAFS also effective Italian catalog, providing good agreement with instrumental catalogue (ISIDE) terms not only number aftershocks, but foreshocks—where fails. These findings suggest foreshocks cannot be solely explained by cascades triggered events, can reasonably considered precursory phenomena reflecting nucleation process main event.