The Usu Volcano is situated at the southern rim of the Toya caldera within the Shikotsu-Toya Nationalpark. The Showa-Shinzan is a lava dome on the east flank of the Usu Volcano. It was formed during the eruptions in the years 1944-45. Rapid ground deformation formed a 150 metres flat topped hill on the lower east flank. The explosive eruptions started on June 23, 1944 and continued almost daily until October 31. The Showa Shinzan is now 398 m (2010) tall, and still actively smoking. A ropeway on Mount Usu takes visitors to viewing platforms overlooking the Showa Shinzan.
Japan 1971, Showa Shinzan.
The stamp is showing the Usu Volcano during the eruptions in the years 1944-45 which formed the Showa Shinzan lava dome.
Japan 2008, Showa Shinzan.