Global Network of National Geoparks

Geopark candidate sites: Unzen and Usu Volcanic area, Japan

Published :April 2, 2008
S. Takarada
Geological Survey of Japan, Aist, 1-1, Higashi 1-Chome. Tsukuba, lbaraki 305-8567, Japan

Keywords: Japan, Unzen, Usu, volcano, eruption

Unzen Volcanic area is located in western Kyushu, Japan. Usu Volcanic area is located in SW Hokkaido, Japan. Both volcanic areas are famous for their beautiful sceneries and wonderful hot springs. A lot of tourists visit these volcanic areas every year. The Unzen Volcanic area is the first national park in Japan since 1934. The Unzen Volcano comprises decide to andesine stratovolcano and dome complex. During the 1991-95 eruptions at the Unzen Volcano formed a new Heisei Shinzan lava dome at the summit. A lot of research works during the eruptions improved the development of volcano logy. Unzen Drilling Project, which successfully penetrated new conduit system, during 1999-2005, also improved scientific aspects of the Unzen Volcano. More than 5 volcanic museums were formed at the Unzen Volcanic area for public educations. The Usu Volcano is located at the southern margin of Toya calderas in the national park. This situation provides one of the most beautiful scenery in Japan.

The Usu Volcano was formed by basaltis-andesitic eruptions since 10,000 years ago. Historical rhyolitic to dacitic eruptions starts from 1663. Totally 9 historical eruptions occurred until 200 eruption formed many lava domes. During 1943-45 eruptions, Showa Shinzen lava dome was formed at the NE foot of the volcano. This lava dome is famous for the Mimatsu Diagram, which made by a local post officer during the World WAR II. The recent 2000 eruption at the Usu Volcano gives us improvement of knowledge of phreatic eruptions. Local community is making a wonderful teamwork to demonstrate this beautiful volcano. After the 2000 eruption, local government and people in the community decided to preserve remnants of impacts of the eruption to make an eco-museum (open field-type museum) for public education. Volcanic hazard maps and many guidebooks were made for educational purpose at Usu Volcanic area.