Updated: August 2007, Jim Chandler
The Black Ven mudslide complex situated between Charmouth and Lyme Regis, Dorset, U.K. is one of the most dynamic landslides in Europe (Figure 1). It consists of three active units separating two dormant systems. It is a famous area for both geologists and geomorphologists because of the fine fossil localities and the perfection of the landforms.
Photogrammetric research carried out at this site solved the problems associated with using historical photographs for spatial measurement. The technique was tested and developed by measuring a fifty year sequence of historical/archival photographs and derived dated Digital Elevation Models (DEMs) to represent the changing morphology of the landslide through time (Chandler & Brunsden, 1995).
A new epoch of photography was obtained by the NERC Remote Sensing Facility in March 1995 following an unusual landslide event which occurred in August 1994. Developments in digital photogrammetry have enabled a new digital elevation model consisting of over 1,000,000 co-ordinates to be measured automatically. The earlier manually measured DEMs consisted of approximately 10,000 points at each epoch and this massive increase in sampling density (a point every 1m) enables very minor morphological features to be recorded automatically, (Figure 2).
Climatic and landslide incidence records have been combined with this precise spatial data. This has allowed the development of an episodic landform change model and provided new insights into predicting landslide events (Brunsden & Chandler, 1996).
In July 2001, NERC acquired a new epoch of aerial photography after a major new landslide event occurred in February 2001. Work is ongoing to process this, other epochs of aerial photography acquired in March 2000 and to merge with airborne laser scanning data acquired by the Environment Agency in 1998 and May 2001. More details of this recent work is available, and includes a series of animations.
Jim Chandler's other research interests