Mount Kusatsu-Shirane erupts after 35 years of calm, leaves one dead and 18 injured
Image credit: Kusatsu-Shirane volcano eruption on January 23, 2018.
A sudden eruption took place at Kusatsu-Shirane volcano (Kusatsu-Shiranesan) in Japan early Tuesday, January 23, 2018, causing an avalanche that left one member of Japan's Self-Defense Forces (SDF) dead and 6 injured. At least 11 people were injured by falling volcanic rocks. It was the first eruption of this volcano since 1983.
The volcano, located near a ski resort in Gunma prefecture, erupted at 01:59 UTC on Tuesday (09:59 local time), spawning an avalanche that buried 6 soldiers and killed one, officials said. All 7 were transported to a hospital where one was later confirmed dead. SDF said at the time that the soldiers were training in the area when the volcano erupted and that they are trying to rescue about 80 people who were visiting the ski resort and evacuated to a ropeway station at the peak.
Falling volcanic rocks injured 11 people, local police said. At least 5 of them were injured after the stones hit a gondola lift, shattering its windows. The injured were treated at a rest house.
Observations by the Tokyo Institute of Technology have confirmed volcanic rocks about 1 km (0.62 miles) from the crater near Kagamiike pond, on Motoshirane peak. Some of the stones appeared to be 10 – 20 cm (3.9 – 7.8 inches) in size.
According to the Tokyo Electric Power Company, a power outage occurred near the ski resort after the eruption.
The Japan Meteorological Agency raised the volcanic alert level to 3, warning people not to approach the volcano. A large amount of ash is present in the area, the agency added, urging elderly, children and others in need of aid during evacuations to begin preparations to leave the area.
JMA said it did not observe any data showing heightened volcanic activity prior to the eruption.


Geological summary
The summit of Kusatsu-Shiranesan volcano, located immediately north of Asama volcano, consists of a series of overlapping pyroclastic cones and three crater lakes. The andesitic-to-dacitic volcano was formed in three eruptive stages beginning in the early to mid-Pleistocene.
The Pleistocene Oshi pyroclastic flow produced extensive welded tuffs and non-welded pumice that covers much of the east, south and SW flanks. The latest eruptive stage began about 14 000 years ago.
All historical eruptions have consisted of phreatic explosions from the acidic crater lakes or their margins. Fumaroles and hot springs that dot the flanks have strongly acidified many rivers draining from the volcano. The crater was the site of active sulfur mining for many years during the 19th and 20th centuries. (GVP)
Teo Blašković founded The Watchers in 2011 and edited it until 2026, covering seismic and volcanic activity, extreme weather, space weather and near-Earth objects. Articles on this page are his archive.
Published in the last 24 hours
- The fastest wind gust ever measured on Earth, 253 mph, hit an oil island off Australia during Cyclone Olivia in 1996, and nobody noticed for more than a decade, until experts reading old data quietly took the record from New Hampshire's Mount Washington Epicenter
- In 1954, a grapefruit-sized meteorite crashed through a roof in Sylacauga, Alabama, and struck Ann Hodges as she napped on her couch Epicenter
- A meteorite blew a crater beside a village near Lake Titicaca in 2007, and dozens of villagers who went to see it got headaches and nausea, though tests found nothing the rock had added to the water Epicenter
- The people who pay closest attention to the weather are the ones storms have already cost the most, a study of 946 students found, with one damaging storm making little difference to how much attention a student paid, but two or more making a clear one Epicenter

