1. PhD Candidate, Dept. of Civil Engineering, Univ. of British Columbia, Vancouver, BC, Canada V6T 1Z4.
2. Associate Professor, Dept. of Civil Engineering, Univ. of British Columbia, Vancouver, BC, Canada V6T 1Z4.
3. Professor, Dept. of Geography, Univ. of British Columbia, Vancouver, BC, Canada V6T 1Z2.