Nasudake

About Nasudake

The Nasudake volcanic group consists of a N-S-trending cluster of stratovolcanoes and lava domes at the north end of the Kanto Plain. Volcanic activity dates back about 500,000 years. Growth of three large basaltic-to-dacitic stratovolcanoes, each lasting about 200,000 years, was followed by construction of three smaller andesitic stratovolcanoes (Asahidake, Futamatayama, and Chausudake). Activity during the last 55,000 years included the collapse of Asahidake ~30-40,000 years ago, producing the massive Ofujisan debris-avalanche deposit, which covers a broad area SE of the volcano. Chausudake, began forming about 16,000 years ago, and has had six known magmatic eruptions, with the latest in 1408-1410 CE that built the summit lava dome formed. These eruptions produced block-and-ash flows and concluded with the extrusion of lava flows. Smaller phreatic eruptions have occurred every few hundred years during the past 5,000 years.