根茂山

Nemo Peak volcano at the northern end of Onekotan Island in the northern Kuriles is truncated by two preglacial nested calderas, the largest of which is 10 km in diameter and extends to the northern coast. A third 5-km-wide caldera formed about 25,000 years ago by collapse of an interglacial cone that was constructed over the glaciated surfaces of the earlier calderas. The central cone of Nemo Peak is composed of two coalescing andesitic cones that were constructed at the SW side of the youngest caldera and formed in four stages beginning in the early Holocene about 9,500 years ago. Construction of the central cone has left the crescent-shaped Chernoe Lake in the NE part of the youngest caldera; lava flows from Nemo Peak form the broad SW shoreline of the lake. The final activity built a lava dome that completely overtops a 350-m-wide crater and has a 150-m-wide crater at its summit. Eruptions from Nemo Peak have been reported since the early 18th century.