The Abu volcanic group ( Japanese 阿 武 火山 群 , Abu-kazangun ) is a group of shield volcanoes that extends along the southwest coast of the Japanese island of Honshū in Yamaguchi prefecture . The group has been active from the late Pliocene to the present Holocene . However, there are no known historical outbreaks. The last dated eruption was 3,400 years ago. The group is formed by more than 40 craters and extends over an area of approximately 400 square kilometers. The Irao-yama volcanic cone is the highest point at 641 m, while the Nabe-yama lava dome is 369 m high. The volcanic activity in this area is related to the subduction of the Philippine plate.
