This image shows the locations of the buried basins detected by the MARSIS sounding radar on board ESA’s Mars Express in July 2005. Locations and inferred diameters from MARSIS echoes are shown in black on a MOLA colour-coded shaded relief.

The locations and diameters of quasi-circular topographic depressions with diameters larger than 200 kilometres are plotted in white. White polygons show the area covered by MARSIS orbits. Where there is left/right ambiguity in the location of a MARSIS basin that coincides with a quasi-circular topographic depression, the plotted location reflects the minimum offset between the centres of the MARSIS basin and the quasi-circular topographic depressions themselves.