From the science column at Wired (U.K.):
The pressure in Mount Fuji's magma chamber is now higher than it was in 1707, the last time the nearly 4,000-metre-high Japanese volcano erupted, causing volcanologists to speculate that a disaster is imminent.Photo: Koichi Kamoshida, Getty Images, via ABC News.
The new readings, taken by the National Research Institute for Earth Science and Disaster Prevention, reveal that the pressure is at 1.6 megapascals, nearly 16 times the 0.1 megapascals it takes to trigger an eruption.
...warned that a massive eruption within three years would be likely because of several major factors: steam and gases are being emitted from the crater, water eruptions are occurring nearby, massive holes emitting hot natural gases are appearing in the vicinity and finally, the warning sign that pushed the professor to make the announcement, a 34km-long fault was found underneath the volcano. The fault, experts suggested, could indicate a total collapse of the mountainside if there is another significant shift, and it would probably cause a collapse in the event of an eruption, leading to huge mud and landslides.