Known sites of hydrothermal venting along mid-ocean ridges, in back-arc basins, rifted arcs, and at submerged island-arc volcanoes (red), and areas of activity as indicated by mid-water chemical anomalies (yellow). EPR = East Pacific Rise. TAG = Trans Atlantic Geotraverse, MEF = Main Endeavour Field, and GR-14 = Sea Cliff hydrothermal field on the northern Gorda Ridge.
(Fig. 1 from Tivey, Oceanogr. magazine, Vol. 20, No. 1, 2007)