Department of Structural & Geotechnical Engineering (DISTR), Politecnico di Torino, Corso Ducadegli Abruzzi 24, 10129 Turin, Italy;
Department of Geography, University at Buffalo, 116 Wilkeson Quad, Amherst, NY 14261, USA;
Department of Civil Structural and Environmental Engineering, University at Buffalo, Buffalo, NY 14260-4300, USA;
College of Politics and Economics, Kyung Hee University, Seoul 130-701, Korea;