Soft copy photogrammetry to measure shore platform erosion on decadal time scales

Shore platform erosion is considered a driving mechanism for cliff recession on many rocky coasts and, in the vicinity of sea defence structures, a threat to their stability, yet the spatial pattern of platform erosion, as well as the rate of lowering, is poorly documented. Measurements based on techniques such as the micro-erosion metre or laser scanner, though highly accurate for short time scales and specific locations, are difficult to extrapolate in space and time. They also fail to record meso-scale changes such as block removal. This paper describes a technique to quantify spatial and temporal changes and presents first results.