Towada volcanTowada volcano is a collapsed large stratovolcano with a 11 km wide dramatic caldera in northern Honshu, Japan. The caldera is occupied by Lake Towada, Japan's largest caldera lake.
The caldera formed during repeated collapse during 6 major eruptions between 53,000 and 13,000 years ago. A new cone grew within the caldera afterwards and collapsed as well, leaving the smaller 2 km wide Nakanoumi caldera nested inside. The SW and NE rims of Nakanoumi form spectacular peninsulas inside Lake Towada.
The only historic eruption of Towada volcano began on 17 August 915 AD from Ogura-yama lava dome near the Goshikiiwa cone on the NE rim of Nakanoumi caldera wall. The eruptions produced widespread ashfalls and pyroclastic flows.
The volcano belongs to Towada-Hachimantai National Park on the border between Aomori and Akita prefectures.
Introduction:Pre-caldera eruptive activity at Towada dates back to about 2 million years ago and produced basaltic-to-dacitic lava cones. Following the late-Pleistocene andesitic-to-rhyolitic caldera-forming eruptions, the basaltic Ninokura stratovolcano grew in the SSE section of the caldera. The successive dacitic-to-rhyolitic Goshikiiwa explosive eruptions led to the formation of the roughly 2-km-wide Nakanoumi caldera. The andesitic-to-dacitic Ogura-yama lava dome was built over the NE rim of Nakanoumi.
(Source: Smithsonian / GVP volcano information)
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