Fault Interaction and the Evolution of Seismicity: the Case Study of the Central Apennine Fault System (CAFS)

This thesis presents an integrated study of the Central Apennine Fault System (CAFS), focusing on the dynamics of fault interactions and the role of Coulomb Stress Transfer (CST) in shaping seismicity. The CAFS, a seismically active region in central Italy, has witnessed numerous destructive earthquakes recorded in extensive national seismic catalogs, making it an ideal subject for investigating the mechanisms underlying seismic events and their respective seismic cycles. In addition to the CAFS, the thesis incorporates findings from a field-based analysis of the Mw 6.4 Petrinja earthquake in Croatia. Although geographically distinct from the CAFS, this study contributes valuable insights into the processes of coseismic faulting and fault interaction in a strike-slip environment, enhancing our understanding of fault dynamics across different tectonic settings. The proposed study spans a variety of tectonic regimes but aims to converge on a detailed examination of fault interaction and the related seismic activity. The primary focus is, therefore, on understanding how the CST influences the activation and interaction of faults within this intricate system in central Italy. A significant aspect of this research involves the analysis of both historical and instrumental seismic events within the CAFS, spanning from the year 1200 AD to the present day. Employing advanced modeling techniques, including innovative three-dimensional elliptical models, the study provides new insights into the role of CST in fault activity. The research demonstrates that CST plays a pivotal role in either promoting or inhibiting seismic events, highlighting the importance of this mechanism in understanding the seismic cycle of the region. This thesis aims to advance the knowledge of Earthquake Geology by providing a comprehensive understanding of the seismic mechanisms within the CAFS and in regions that are geographically and geologically distinct (e.g., Petrinja, Croatia). The findings of this research might have significant implicationsfor seismic hazard assessment and risk management, contributing to the development of targeted seismic risk mitigation strategies and enhancing efforts in earthquake preparedness and response in seismically active regions.