Geological map of the southern part of the Main Endeavour vent field, adapted from [43]. The acoustic recording system was deployed at the Sully and Puffer vents in September 2004 and 2005 respectively. On this map, dark gray objects represent active sulfide structures; light gray objects represent inactive sulfides or diffuse vents; triangles depict talus at the base of the west axial valley wall; and thin lines indicate faults and fissures. Inset shows the location of the Juan de Fuca Ridge in the northeast Pacific Ocean, approximately 500 km west of Seattle, WA, with the location of the Main Endeavour Field (MEF) marked with a star. Surrounding plate boundaries are also depicted.