(a)

(b)

(c)

Figure 5: Detailed maps of seep sites. (a) Joetsu Knoll center, (b) Umitaka Spur north, and (c) Umitaka Spur center. See Figures 1 and 4 for map locations. Yellow circles indicate giant plumes observed by echosounder during the last few years [12]. Red ellipses indicate mound seep site regions with giant plumes. Red stars indicate gas hydrate outcrops.