Improved understanding of spatio-temporal variations in fault activity using high resolution geomorphic markers

Recent developments in single grain K-feldspar IRSL (Infra-Red Stimulated Luminescence) dating of sediment coupled to high resolution surface morphology provides significant new opportunities to explore active fault, and fault system, behaviour over multiple earthquake cycles. Results from California and New Zealand demonstrate systematic variations in fault slip rate over multiple earthquake cycles. In New Zealand, sub-parallel faults within the Marlborough Fault System demonstrate complementary behaviour; as slip rate on one fault reduces, slip speeds up on another or others. The construction of these records depends on developing detailed chronologies of multiple slip events on each fault, and on reconstructing past fault slip with geomorphic markers. The approaches that our interdisciplinary collaborative team has developed to do this will be presented, along with an assessment of the reliability of the reconstructions, in particular the dense chronologies that are developed. New avenues to add further resolution and robustness to these approaches will be considered, along with innovative ideas to co-develop palaeoclimate and environmental reconstructions, and build an improved understanding of sediment grain transport trajectories.