Koniuji Island

Koniuji Island is the emergent top of a mostly submarine stratovolcano. Little is known of the geologic history of this volcano. Reports of recent eruptive activity may be erroneous and are considered to refer to eruptions of Kasatochi volcano to the west. The last eruption of Koniuji Island was around 3,000 years ago, in approximately 1150 BC.