The volume of magma of the petit spot volcanoes (Hirano et al., 2006) has not been estimated but certainly must be several orders of magnitude less than surrounding Cretaceous volcanoes on the NW Pacific Plate. Note that we found 0-1, 2.5, 4.2, 6.0 and 8.6 Ma volcanoes, implying episodic eruption of magma over a distance of 600 km of plate motion on the flexural Pacific Plate before its subduction but with low volumes of magma production.