Backgroundfrom Smithsonian / GVP volcano information:
The Kuttara group was constructed during 5 major eruptive stages, the first of which occurred more than 60,000 years ago. A major dacitic pumice eruption at the end of the 4th stage about 40,000 years ago resulted in the formation of the 3-km-diameter Kuttara caldera. The caldera cut a basaltic-to-andesitic stratovolcano complex, which late in its activity produced two major andesitic lava flows on its north side at Kita-yama. Explosions, probably in early Holocene time, formed two large craters on the west flank of the caldera, and a dacitic lava dome was emplaced about 10,000 years ago. Late-stage phreatic explosion products from Jigoku-dani, a 300-400 m wide crater south of the lava dome, overlie the 1663 tephra from Usu volcano. Jigoku-dani and Noboribetsu Spa are the sites of intense thermal activity, including fumaroles, hot springs, and geysers.
See also: Sentinel hub | Landsat 8 | NASA FIRMS