The rift valley geomorphic feature layer represents the spatial extent of the rift valleys of the worlds oceans based on interpretation of the SRTM30 plus v7 global bathymetry model. The layer is one of the 25 layers that make up the global seafloor geomorphic features map (Harris et.al. 2014). Rift valleys were mapped as separate features in the present study where they are clearly evident in SRTM30_PLUS bathymetric data. Rift valleys are confined to the central axis of mid-ocean spreading ridges; they are elongate, local depressions flanked generally on both sides by ridges (Macdonald, 2001). They were mapped by hand based on 100 m contours.