Australia's new ocean-going research vessel RV Investigator has discovered extinct volcanoes about 250 kilometres off the coast of Sydney in 4,900 metres of water. Professor Richard Arculus, from the ANU Research School of Earth Sciences, an igneous petrologist and a world-leading expert on volcanoes said these particular types of volcanoes are windows into the seafloor.
Read the full article "Submerged volcano cluster found off the coast of Sydney", published by the Australian National University on 13 July 2015.
3D view of multibeam swath over volcanoes