Kasuga 1

Kasuga 1 is a seamount and active volcano of the Mariana volcanic arc. It rises above the seafloor to about beneath the ocean surface. The volcano represents the northernmost of the three that forms the Kasuga seamount chain and is located southeast of Fukujin. Its last confirmed eruption was in July 1959 which produced pumice and another possible eruption may have occurred in 1975 when discolored water was observed around the seamount. Based on the samples of basalt and andesite collected at the summit, it is the oldest of the seamounts.