SpuriousLogic points out an article at Wired discussing research into pressure levels inside Mt. Fuji's magma chamber, which scientists claim is higher than it was in 1707, the last time it erupted
. "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." A series of earthquakes shook the area around Mt. Fuji a little over a decade ago, and a fault line was discovered underneath it. "Since the March 2011 tsunami and the 6.4 magnitude earthquake that followed four days later, Japan has been on tenterhooks, and in May 2012 a professor from Ryukyu University 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." While the rising pressure within the magma chamber is of concern, it is but one factor among many that lead to eruptions.