1. Research Department 4 ‐ Dynamics of the Ocean Floor Helmholtz Centre for Ocean Research, GEOMAR, Kiel Wischhofstr. 1‐3 Kiel 24148 Germany
2. Department of Geophysics Colorado School of Mines Golden CO 80401 USA
3. Department of Geoscience, Institute of Geophysics and Meteorology University of Cologne Cologne 50963 Germany