Figure 1: The CSEM study centred at 57°45 ' N on the Reykjanes Ridge. The inset shows the location of the RAMESSES experiment (square), with bathymetric contours at 800 m intervals from sea level. Bathymetry of the work area, shaded at depths greater than 1800 m, is derived from the gridded swath bathymetry data collected during the RAMESSES experiment. The CSEM instrument positions and DASI tow lines are shown. Tow 1 ran down the crest of the AVR. Tow 2 was 4 km to the West of the AVR. Instruments were deployed along and across the AVR coincident with the wide-angle seismic lines. Different symbols show the instrument positions and types. The arrows on the LEM instruments show the directions of their 300 m long antennae. Also shown are the positions of the navigation transponders used in determining the source position.