1. Professor, School of Civil Engineering and Geosciences, Univ. of Newcastle-upon-Tyne, Cassie Building, Newcastle-upon-Tyne NE1 7RU, UK.
2. Scientific Functionnaire, Institute for Protection and Security of the Citizen, European Commission Joint Research Centre, Via Fermi, 1 21020 Ispra (VA), Italy.
3. Professor, School of Geographical Sciences, Univ. of Bristol, University Rd., Bristol BS8 1SS, U.K.
4. Research Fellow, School of Geographical Sciences, Univ. of Bristol, University Rd., Bristol BS8 1SS, U.K.