Ontake-san volcano news & activity updates:
Ontake-san volcano (Japan): large explosion kills at least 1 person, several injured
Saturday Sep 27, 2014 20:59 PM | DOOR: T
A large explosive eruption occurred at Japan's second highest volcano today at 11:56 local time. An explosion produced an ash plume that rose approx. 4 km and a large pyroclastic flow that swept down the southwestern flank.
Pyroclastic flow during Ontake volcano's eruption today (Asahi.com)
At least one woman was killed by the eruption and several others, approx. 50 persons, were severely injured. The volcano is a popular hiking destination and at the time of the eruption, about 150-200 people were on the volcano.
A temple near the summit area was also strongly affected by the eruption.
Most likely, the eruption was phreatic in nature, i.e. caused by overheated ground water that suddenly exploded into steam and pulverized large amounts of rocks in the conduit.
The last known (and first historic) magmatic eruption on the volcano was between Oct 1979 and April 1980. Small phreatic explosions occurred in 2007.
Impressive video from the eruption (Asahi)