Mount Unzen was designated a Decade Volcano by the United Nations, in 1991 as part of their International Decade for Natural Disaster Reduction, due to its history of violent activity and location in a densely populated area.

Daily number of earthquakes (top) and tremor episodes (bottom) at Unzen, January-18 June 1991. Arrows represent resumption of explosive activity on 12 February and dome appearance on 20 May 1991. Courtesy of JMA. Phreato-magmatic activity, February-May.

Unzen (on the Shimabara-hanto Peninsula, a two hour drive from Nagasaki) was a popular seaside and highland hot spring resort up until 1991, when a violent volcanic eruption produced a huge fire-ball-like wall of incandescent gas that killed 43 people including two of the world's most famous volcanologists (See Below). Mt.

Jun 9, 1991 · TOKYO — Mt. Unzen, a volcano that claimed at least 37 lives less than a week ago, burst to life again Saturday, spewing hot debris that set homes on fire and blacking out a nearby city of...

Jun 18, 1991 · Three AGU members were among 37 people killed June 3 when Mount Unzen, a volcano in Nagasaki prefecture, Japan, erupted. Unzen last erupted in 1792. The first signs of renewed activity appeared in mid-1990, with increases in seismicity and the first volcanic tremor since observations began in 1966.

Daily number of recorded earthquakes (top) and tremor episodes (bottom) at Unzen, June 1990-early February 1991. Arrows mark small eruptions on 17 November and 12 February. Courtesy of JMA. Tremor began to be detected on 25 January . . . .

Nov 17, 1990 · Bulletin of the Global Volcanism Network, vol. 16, no. 6 (June 1991) Managing Editor: Lindsay McClelland. Unzendake (Japan) Continued lava dome growth; debris flows to 7.5 km destroy houses; evacuations prevent more casualties

Jun 4, 1991 · Soldiers in firefighting gear ventured Tuesday into the shadow of a suddenly ferocious volcano, recovering four bodies and sighting 24 others before being turned back by Mount Unzen's searing gas, ash and rock.

Jun 4, 1991 · The eruption of Mount Unzen, about 30 miles from Nagasaki on the southern island of Kyushu, appeared to be among the largest volcanic eruptions in Japan in at least half a century.

Unzen Volcano (Mt Fugen / Fugendake) The 1990-1995 eruption of Unzen volcano is infamous for the 43 fatalities caused by the unexpectedly large pyroclastic flow on June 3, 1991.