Echo Sounder Outlines Strange Patches Over Underwater Peaks
February 11, 1977, on the s.s. Remuera, in the South Pacific. (00° 24'S, 88° 06' W). The echo sounder clearly showed an undulating sea floor with sharp peaks, some 600 fathoms below the ship. The peaks were recorded distincly but above several faint, elongated, flamelike patches were noted. These patches were interpreted as changes in water density due, perhaps, to volcanic or hydrothermal activity.
(Howard, K.E.; "Soundings in a Volcanic Area," Marine Observer, 48:20, 1978.)