Affiliation: | WesternGeco Product Technology Centre, Oslo, Solbraaveien 23, 1383,;Asker, Norway. E-mail: Schlumberger Cambridge Research, High Cross, Madingley Road, CB3 0EL,;Cambridge School of GeoSciences, University of Edinburgh, Grant Institute, West Mains Road, EH9 3JG,;Edinburgh Department of Geophysics, Utrecht University, PO Box 80021, 3508;TA, Utrecht, the Netherlands |