Report on Niigata-Yakeyama (Japan) — December 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 12 (December 1991)
Managing Editor: Lindsay McClelland.
Niigata-Yakeyama (Japan) Increased steaming
Please cite this report as:
Global Volcanism Program, 1991. Report on Niigata-Yakeyama (Japan). In: McClelland, L. (ed.), Bulletin of the Global Volcanism Network, 16:12. Smithsonian Institution.
36.921°N, 138.036°E; summit elev. 2400 m
All times are local (unless otherwise noted)
Steaming from vents near the summit has increased slightly since October. A seismometer installed near the volcano on 20 December recorded only 1 weak earthquake by 16 January. Steam emission has continued since late April 1987 (figure 1), when a small ash ejection occurred. Larger plumes in April 1989 also included ash.
Geologic Background. Niigata-Yakeyama, one of several Japanese volcanoes named Yakeyama ("Burning Mountain"), is a very young andesitic-to-dacitic lava dome in Niigata prefecture in central Honshu, near the Japan Sea. The small volcano rises to 2400 m and was constructed on a base of Tertiary mountains 2000 m high beginning about 3100 years ago. Three major magmatic eruptions took place in historical time, producing pyroclastic flows and surges and lava flows that traveled mainly down the Hayakawa river valley to the north and NW. The first of these eruptions took place about 1000 years ago (in 887 and possibly 989 CE) and produced the Hayakawa pyroclastic flow, which traveled about 20 km to reach the Japan Sea, and the massive Mae-yama lava flow, which traveled about 6.5 km down the Hayakawa river valley. The summit lava dome was emplaced during the 1361 eruption, and the last magmatic eruption took place in 1773 CE. Eruptive activity since 1773 has consisted of relatively minor phreatic explosions from several radial fissures and explosion craters that cut the summit and flanks of the dome.
Information Contacts: JMA.