1. European Centre for Training and Research in Earthquake Engineering (EUCENTRE), 27100 Pavia, Italy
2. Imperial College London, Civil & Environmental Engineering, London SW7 2AZ, U. K.
3. University of Pavia, Department of Structural Mechanics, via Ferrata 1, 27100 Pavia, Italy;
4. European School for Advanced Studies in Reduction of Seismic Risk (ROSE School), 27100 Pavia, Italy
5. Department of Civil Protection, National Seismic Service, via Vitorchiano 2, 00189 Rome, Italy
6. Italian Institute for Geophysics and Volcanology (INGV), via Bassini 15, 20133 Milan, Italy