The summit of Nasu-Chausudake volcano, Japan Chausudake volcano is the only active volcanic cone of the Nasu volcanic group, about 160 km north of Tokyo. The products of Chausudake volcano are composed of six magmatic eruption units and more than 12 phreatic eruption units. The magmatic eruptions occurred at about 16 ka (Osawa unit), 11 ka (Yumoto unit), 8 ka (Yahata unit), 6 ka (Omaru unit), 2.6 ka (Minenochaya unit), and 1408-1410. The summit of Chausudake is made up of the ejecta of the 1408-1410 eruption that is composed of phreatic fallouts (white part) and an overlying andeaitic lava flow. (Takahiro Yamamoto) |