Isobel Yeo of GEOMAR’s Helmholtz Institute for Ocean Research Kiel is calculating the date of lava flows from undersea volcanoes by using the reflectivity returned by sonar backscatter. Nice article on the BBC website here http://www.bbc.com/earth/story/20160808-the-volcanoes-hiding-in-the-ocean and her paper can be downloaded here http://www.sciencedirect.com/science/article/pii/S0012821X16000510