1. Engineering Geology and Geophysics Group, British Geological Survey
Keyworth, Nottingham, NG12 5GG, UK
2. Department of Earth Sciences, Beaumont Building, University of Sheffield
Brookhill, Sheffield, S3 7HF, UK
3. Department of Geology and Applied Geology, University of Natal
King George V Avenue, Durban 4001, South Africa
4. School of Construction, Sheffield City Polytechnic
Pond Street, Sheffield, SI 1WB, UK