1. Assistant Professor of Engineering, Dept. of Civil Environmental and Architectural Engineering, Univ. of Genova, 16145 Genova, Italy.
2. Research Assistant Professor, NatHaz Modeling Laboratory, Univ. of Notre Dame, Notre Dame, IN 46556 (corresponding author).
3. Robert M. Moran Professor of Engineering, NatHaz Modeling Laboratory, Univ. of Notre Dame, Notre Dame, IN 46556.