While mapping Vailuluʻu Seamount in 2017, backscatter data collected with NOAA Ship Okeanos Explorer’s multibeam sonar system revealed a plume of bubbles rising from the seafloor, suggesting the presence of hydrothermal activity. In this image, the plume is visible in the water column backscatter (the blue and green cone) overlaid on the seamount’s bathymetry.

From: A Tantalizing Preview of Vailulu'u Seamount