HR: 14:55h
AN: P33D-06 INVITED     [Abstracts]
TI: The Application of Terrestrial Laser Scanning Techniques to the Investigation of Mechanisms of Mass Movement
AU: * Petley, D
EM: d.n.petley@durham.ac.uk
AF: International Landslide Centre, Department of Geography University of Durham, Durham, DH1 3LE United Kingdom
AU: Rosser, N
EM: nick.rosser@durham.ac.uk
AF: International Landslide Centre, Department of Geography University of Durham, Durham, DH1 3LE United Kingdom
AU: Dunning, S
EM: stuart.dunning@durham.ac.uk
AF: International Landslide Centre, Department of Geography University of Durham, Durham, DH1 3LE United Kingdom
AU: Lim, M
EM: michael.lim@durham.ac.uk
AF: International Landslide Centre, Department of Geography University of Durham, Durham, DH1 3LE United Kingdom
AU: Allison, R
EM: r.j.allison@durham.ac.uk
AF: International Landslide Centre, Department of Geography University of Durham, Durham, DH1 3LE United Kingdom
AB: A key challenge in the understanding of the mechanisms through which mass movement events occur is the development of proper measurements of strain across the mobile material. Conventional instrumentation, such as inclinometers and extensometers, provide high quality data, but only for a single point on the landslide. Interpretation of the movement of the whole mass thus requires considerable interpolation, introducing high levels of uncertainty. Similarly, the analysis of fall events has proven to be difficult because of the challenges of obtaining high quality precursory strain data and of assessing the actual geometry and location of the detached material. Terrestrial laser scanning technologies offer a solution to many of these problems, permitting high precision measurements of the surface of mobile, or potentially mobile, masses. Repeat scans, which can be analysed through the application of sophisticated mesh subtraction methods, permits the comparatively simple generation of comprehensive deformation maps, potentially resolving both pre- and post-failure deformations. The research presented in this paper has focussed upon the development of terrestrial laser scanning technologies for mass movement analysis. Were our focus is rock cliffs, where the technology has been used to examine the processes through which rockfalls are generated. The change maps from mesh subtraction have been used to examine the temporal and spatial distributions of the rockfall events. These data have been synthesised with other environmental datasets collected at the site, including air temperature, precipitation, cliff top groundwater level, wave-induced seismic energy release, joint geometry, and lithology. The magnitude - frequency relationships for rockfalls from the cliff as a whole, and from specific lithologies and areas of jointing, have been examined in the context of these environmental factors. The key role played by wave impacts and rainfall events has been highlighted. It is clear that existing models of cliff evolution, such as those that advocate mechanisms based upon notch formation at the cliff toe, oversimplify the dynamics of coastal cliff systems. Thus the research highlights how the new levels of data quality obtained through terrestrial laser scanning can permit new insights into mass movement processes to be gained.
DE: 1810 Debris flow and landslides
DE: 5415 Erosion and weathering
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 5494 Instruments and techniques
SC: Planetary Sciences [P]
MN: Fall Meeting 2005