Seismic Monitoring in Sicily: Insights from ETAS and Magnitude of Completeness Approaches

Seismic activity is a fundamental characteristic of tectonically active regions, and Sicily represents a key area for understanding seismic processes in the Mediterranean. This study presents a comprehensive survey of seismic activity in Sicily using the Epidemic-Type Aftershock Sequence (ETAS) method and a detailed analysis of the magnitude of completeness (Mc). By integrating these two approaches, we aim to enhance our understanding of seismicity patterns and assess the seismic hazard in the region.

The ETAS model, widely used in seismology, enables the separation of background seismicity from earthquake clusters, such as aftershocks and swarms. We employed this method to model seismic events recorded in Sicily over a multi-year period, using data from local and regional seismic networks. By estimating key ETAS parameters, including productivity, aftershock decay rate, and spatial clustering, we provide insights into the temporal and spatial distribution of seismicity. Our analysis reveals significant variability in seismic clustering across different tectonic domains in Sicily, reflecting the complex interplay of crustal structures and active fault systems.

In parallel, the Mc was evaluated to determine the reliability of the seismic catalog used. The Mc defines the lowest magnitude at which all earthquakes in a given dataset are reliably detected, making it a critical parameter for seismic hazard assessment. Through statistical techniques such as the maximum curvature method and goodness-of-fit tests, we assessed Mc spatially and temporally. Results indicate that Mc varies significantly across the region, influenced by factors such as network density, station sensitivity, and local noise conditions. Areas with lower Mc values, such as the eastern coast near Mount Etna, provide a higher resolution of seismic activity compared to regions with sparser network coverage.

By combining ETAS modeling with Mc analysis, this study highlights the importance of comprehensive seismic monitoring in seismically active regions like Sicily. Our findings show that the seismicity is highly influenced by the region’s tectonic complexity, which includes the convergence of the African and Eurasian plates, active subduction processes, and the dynamic volcanic activity of Mount Etna. These factors contribute to the heterogeneous distribution of seismicity and underscore the need for tailored monitoring and modeling strategies.

The results have important implications for seismic hazard assessment in Sicily. The ETAS model allows for the probabilistic forecasting of aftershock sequences. Additionally, understanding Mc distribution enhances the reliability of seismic catalogs, which are fundamental for evaluating seismic risk and improving earthquake preparedness.

In conclusion, this study demonstrates the utility of combining the ETAS method with Mc analysis to achieve a deeper understanding of seismic activity in Sicily. The integration of these methodologies not only refines the characterization of seismicity but also provides actionable insights for regional seismic hazard mitigation efforts.