Exploring Offshore Hydrothermal Venting Using Low-Cost ROV and Photogrammetric Techniques: a Case Study from Milos Island, Greece

The study utilises two emerging low-cost technologies, low cost Remotely Operated Vehicle (ROV) and underwater photogrammetry techniques (Structure from motion (SfM)) using off the shelf cameras, for 3D reconstruction of shallow hydrothermal vent sites around Paleochori Bay, Milos Island, Greece. Venting fields were Characterised through interactive bathymetry models produced from still images taken from camera onboard ROV flown over areas of interest in double raster pattern. This is the first time the shallow venting fields on Milos have been actively surveyed using the combined approach of ROV and photogrammetry. Areas were successfully surveyed and the bathymetry was reconstructed using SfM photogrammetry with a ~10 cm scale resolution. A diverse range of benthic habitats were surveyed and the resulting topographic models will act as a baseline for an established method, that given with positioning will provide further characterisation of the vent systems and any evolving seafloor morphology.