Volcanic gases from the submerged caldera of Sakurajima Volcano are ch
aracterized by He-3/He-4 = 6.1R(A), CH4/He-3 almost-equal-to 10(9), an
d a ratio of excess SIGMACO2 to He-3 of 140 x 10(9). Helium in the Kag
oshima Bay waters is a mixture of volcanic helium and atmospheric-solu
bility helium in surface waters, and provides a strong signature for s
eawater injected into the protocaldera by flow through the volcanic ed
ifice, the probable source of the warm deep water that replaces the co
lder, more saline deep water of the North Basin in November.