High-resolution aftershock-based imaging of active faults, source parameters and earthquake driving mechanisms a contribution to seismic hazard assessment in northeastern Algeria

Abstract

The present thesis, titled "High-Resolution Aftershock-Based Imaging of Active Faults,Source Parameters, and Earthquake Driving Mechanisms: A Contribution to Seismic Hazard Assessment in Northeastern Algeria" builds upon these developments. The main aim is to contribute valuable insights to the assessment of seismic hazards in the northeastern region of Algeria. The thesis is structured around three core components. First, it focuses on high-resolution aftershock-based imaging, providing detailed depictions of fault systems to improve the understanding of fault geometries and potential earthquake nucleation zones. Utilizing advanced techniques such as double-difference relocation and hierarchical clustering of earthquake multiplet, this work identifies previously unmapped fault segments. Second, it involves the analysis of earthquake source parameters, including seismic moment, fault geometry, stress drop, and source radius. These parameters provide crucial insights into earthquake mechanics and the characteristics of faults in the study area. Third, the research investigates earthquake driving mechanisms, including tectonic loading, stress transfer, fluid intrusion, and aseismic slip, to unravel the complex factors contributing to earthquake occurrence in this tectonically active region. Our research began with a detailed analysis of the Beni-Ilmane sequence 2010, serving as a foundation for generalizing our methodology to seismic sequences that occurred between 2007 and 2022 across northeastern Algeria. By analyzing seismic sequences from 2007 to 2022, this research compiles a comprehensive database of active faults, seismic parameters, and earthquake mechanisms. The Findings serves as a critical resource for evaluating seismic hazard and developing risk mitigation strategies. This work highlights the importance of integrating seismic data, fault imaging, and earthquake modeling to enhance the resilience of infrastructures in northeastern Algeria against future seismic events.