Integrated Seismological Approaches for Source Characterisation and Site Amplification Analysis

This thesis presents a comprehensive study aimed at enhancing the understanding of seismic phenomena in specific regions of Italy through methodological innovations applied to case studies. By investigating key seismological parameters – including source characteristics and local site effects – this research provides valuable insights for improving seismic hazard assessment and risk mitigation. The initial focus is on the characterisation of seismic sources using spectral methods. The application of the Generalised Inversion Technique to a data set of about 30,000 earthquakes in the Apennine region (2005–2023) highlights the importance of region-specific attenuation models to reduce epistemic uncertainties in the estimation of the seismic moment and the corner frequency. The analysis shows significant spatial variability in stress drop, highlighting the differences between the Tyrrhenian and Adriatic domains and identifying depth-dependent stress-drop variations in notable seismic sequences such as Amatrice–Norcia–Visso 2016–2017 and L’Aquila 2009. The necessity of accurate and consistent seismic source parameter estimation extends beyond individual case studies to broader regional monitoring efforts. Building on this principle, a new catalogue of moment magnitude (Mw ) estimates for northeast Italy (2016–2023) is presented, based on over 11,600 low-to-moderate magnitude earthquakes. These Mw values were obtained using a Python routine developed for near–real-time integration into the seismic monitoring system of the National Institute of Oceanography and Applied Geophysics – Centre for Seismological Research. This catalogue enables improved magnitude-recurrence relationships and supports more accurate ground motion prediction equations. It is accessible online to the scientific community and encourages collaboration and further research, improving our understanding of geodynamics and seismic hazards in northeast Italy and surrounding areas. The need to improve data accessibility and promote scientific collaboration was also the reason for the development of STATION (Seismic sTATion and sIte amplificatiON; https://distav.unige.it/rsni/station.php), a web service and platform with a user-friendly design that provides continuous updates of site-specific seismological characteristics from over 2,500 seismic stations in Italy and neighbouring regions. By utilising data from around 120,000 recorded earthquakes (2005–2024), STATION provides important information for seismic monitoring, seismic microzonation and post-event analysis. While the study of recent seismic events benefits from well-established methodologies, the investigation of historical earthquakes – particularly in terms of quantitative re-evaluation of their source parameters – presents a far greater challenge. To address this, the final part of this work focusses on the 1887 Ligurian earthquake, one of the most significant seismic events in southwest Europe. By digitising historical magnetometer recordings, the study provides the first quantitative analysis of the earthquake’s ground shaking. Synthetic seismograms identify a low-angle, north-dipping reverse fault as the most plausible source. This contributes to clarifying the debates about the focal mechanism of the fault responsible for the event and demonstrates the value of historical data in quantitative seismological research, especially in regions with low-to-moderate seismicity but potential for strong earthquakes. In summary, this work emphasises the importance of multidisciplinary approaches in seismology that combine data-driven innovation with case-specific applications to advance seismic monitoring and hazard assessment, laying the foundation for future improvements in earthquake research.