Strain accommodation along major rift-bounding faults of an early-stage continental rift: Evolution and growth of normal faults of the Malawi Rift

This dissertation explores the dynamics of fault systems and strain accommodation in the Southern Malawi Rift through a series of interrelated studies. The first project investigates the segmentation, linkage, and growth of the Bilila-Mtakataka Fault (BMF) System, integrating high-resolution topographic, electrical resistivity tomography (ERT), and aeromagnetic data. This approach reveals discrepancies between surface and subsurface fault characteristics, highlighting a more complex long-term evolution of the BMF than previously assumed. Our findings indicate that despite its extensive length, the BMF is under-displaced compared to global fault populations, suggesting it may continue to accumulate strain, posing a major seismic hazard. The second project addresses the challenge of accurate fault throw estimation by developing a novel semi-automated MATLAB algorithm. This algorithm integrates surface and subsurface datasets, including Shuttle Radar Topography Mission (SRTM-DEM) and aeromagnetic data, to enhance fault throw estimates. By incorporating subsurface depth-to-magnetic basement data, the algorithm overcomes the limitations of traditional surface-only methods, providing analysis of fault throw distribution, segmentation, and growth. This advancement improves the accuracy and efficiency of fault analysis, offering valuable insights for seismic hazard assessments. The third project focuses on strain accommodation within the bifurcating zone of the Malawi Rift, specifically along the major faults. Using a multidisciplinary approach that combines ERT, aeromagnetic data, and InSAR time-series analysis, we investigate variations in fault structures and deformation patterns. Our results reveal complex interactions between major and inner-rift faults, with equally substantial ground displacement and subsidence observed near the border and intra-rift faults. This study enhances the understanding of geospatial variation due to rift bifurcation, fault dynamics, and strain partitioning, providing insights for regional seismic hazard assessment and resource management. These studies offer a view of fault dynamics and strain accommodation in the Southern Malawi Rift, integrating advanced methodologies to improve fault analysis and seismic hazard evaluation.