1. Department of Mathematics and Physics Universitella Campania—Luigi Vanvitelli Caserta Italy
2. Istituto Nazionale di Geofisica e Vulcanologia—Sezione di Napoli Osservatorio Vesuviano Napoli Italy
3. Escuela Centroamericana de Geologia Universidad de Costa Rica San José Costa Rica
4. Instituto Costarricense de Electricidad San José Costa Rica
5. The Institute of Statistical Mathematics Research Organization of Information and Systems Tokyo Japan