Mount Asama (浅間山) is an active volcano on central Honshu, the main island of Japan, on the border between Gunma and Nagano prefectures. Mt. Asama stands 2,560 m above sea level. It erupted most recently on September 1, 2004. Previous noteworthy eruptions occurred in 685, 1108, 1783, and 1972; lesser activity has been recorded on dozens of occasions. The eastern slope has a volcano observation station run by Tokyo University.