When the Wadati-Benioff zone (earthquake foci in the mantle) is less than 200 km deep, tholeiitic basalt magmas are produced (Izu Ōshima, Mount Hakone for instance). At intermediate depths high-alumina basalt magmas are formed (Mount Fuji, Southern Yatsugatake Volcanic Group, Mount Ontake, for instance) and at depths greater than 250 km alkali olivine basalt ones (Oki-Dōgo, for instance). Hisashi Kuno contributed to unfold this causal correlation.