Robert S White¹, Jennifer Woods², Tom Winder², Bryndís Brandsdóttir³, Thorbjorg Agustsdottir⁴ and Thomas Hudson⁵, (1)Bullard Laboratories, Cambridge, CB3, United Kingdom, (2)University of Cambridge, Cambridge, United Kingdom, (3)Science Institute, University of Iceland, Nordic Volcanological Center, Institute of Earth Sciences, Reykjavik, Iceland, (4)University of Cambridge, Department of Earth Sciences, Cambridge, United Kingdom, (5)Bullard Laboratories, Cambridge, United Kingdom