Last Saturday, September 27, just before noon, the volcano Ontake, around 250 kilometres northeast of Kyoto erupted in what is called a phreatic explosion. This is caused by water being almost instantly turned to steam (by the volcano’s magma) and then exploding through the surface. While this sounds rather harmless compared to a full-blown eruption with liquid magma, the images (you have seen them by now) tell another story. 
So far, 36 people are presumed to be dead, and at least 63 have been injured, some of them severely. Given that there were around 250 people near the peak of the volcano at the time of the eruption, it could have been much worse, but still… Here is a link to the latest news from Japantimes, complete with videos and photos: article from www.japantimes.co.jp
Mount Ontake, with 3067 metres, is the second highest volcano in Japan, the highest one is Fuji. Since olden times, it has been a sacred place complete with shrine and everything; apparently it is especially popular with artists and actors who go there to seek enlightenment and inspiration in trance and meditation. Even for those of less artistic bent, Mount Ontake is a popular hiking destination. It belongs to the list of 100 famous mountains in Japan, and Ni-no-ike, one of its five crater lakes, is the highest crater lake in the country. It seems to be relatively easy to climb the mountain, and thus, around this time, when the leaves begin to turn, many Japanese nature lovers visit the mountain and the area.