Landslide Laser Scanning: a new look at an old problem

Abstract

An essential part of the study of any landslide problem is the development of a 3-D conceptual model of the landslide and its surroundings. Traditionally this has been done by pen and paper during a walk-over geomorphological survey (Forster 1989) ideally with pits and boreholes to give subsurface information. More recently aerial photographs and aerial ortho-photographs have aided the surface assessment and geophysical surveys have added to the understanding of the third dimension. A more detailed quantitative model could be achieved by accurate ground surveying by EDM, theodolite and level. However, this is time consuming and a high degree of surveying expertise is necessary for an accurate result where small movements might need to be monitored. More recently ‘total station’ surveying equipment has increased the speed at which this process can be completed. However, the advent of affordable semi-automated laser scanners and accurate differential GPS technology has opened up a new opportunity in rapid landslide modelling. The British Geological Survey is currently using and developing laser scanning for the characterization, modelling and monitoring of landslides, essentially a terrestrial LIDAR technique (Hobbs et al. 2002). A small part of that work has been looking at two landslides in the Cotswolds, in association with the School of Earth and Environmental Sciences of the University of Portsmouth, which has a major research interest in studying the landslides in the Jurassic strata near the village of Broadway in …