1. CEA/DAM/DIF; Arpajon; France
2. BGR; Hannover; Germany
3. AWE Blacknest; Reading; UK
4. Dipartimento Scienze della Terra; Università di Firenze; Firenze; Italy
5. Swedish Institute for Space Physics; Umea; Sweden
6. NORSAR; Kjeller; Norway
7. Icelandic Meteorological Office; Reykjavík; Iceland
8. Institute of Earth Sciences; University of Iceland; Reykjavík; Iceland