Regional-scale proximal to distal footwall scarp-degradation variability of extensional faults

Abstract

<p>Footwall fault scarp-degradation produces sediments resulting in gravity-driven syn-rift wedge-shaped deposits located on the immediate hangingwall. To understand which aspects control footwall scarp-degradation we propose a model suggesting where, why, and how degradation occurs. We compare five offshore 3D seismic surveys acquired on the Northern Carnarvon Basin (North West Shelf of Australia) calibrated with well data to assess these questions. Two 3D seismic surveys (i.e., Panaeus 2001 East and Fortuna) are located on the Dampier Sub-basin, proximal to the Western Australia coastline and three (i.e., Thebe, Bonaventure and Agrippina) in a more distal position on the Exmouth Plateau. Data show that degradation is more pronounced on the distal surveys compared to the proximal ones. On the proximal surveys, the sedimentation rate is greater than in the distal ones, and footwall scarp-degradation is less pronounced. Answering these questions will help us to predict the style and the amount of footwall scarp-degradation in similar extensional settings.</p>