Myoko volcanMyoko volcano is a steep basaltic-to-dacitic stratovolcano north of Nagano City that overlooks the popular resort of Lake Nojiri below its SE flank.
Myoko's summit is formed by a lava dome filling most of a 3-km-wide caldera which is widely breached to the east.
No historical eruptions are known at Myoko, but there is constant solfataric activity between the dome and the south caldera wall at a place where sulfur was once mined.
Introduction:Myoko volcano was constructed during 4 stages beginning about 300,000 years ago, each evolving from basaltic to andesitic and dacitic eruptions. The latest eruptive stage began about 43,000 years ago. Several episodes of edifice collapse at Myoko during the late Pleistocene to early Holocene have produced major debris avalanches that traveled to the east and NE. Myoko produced pyroclastic flows down the eastern flanks of the volcano during the mid Holocene about 5800 and 4200 years ago, and the latest dated eruption produced pyroclastic surges about 2800-2500 years ago.
from: Myoko volcano information (Smithsonian / GVP)
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