<Li> November 11, 1707 (Hōei 4, 14th day of the 10th month): The city of Osaka suffers tremendously because of a very violent earthquake . </Li> <Li> December 16, 1707 (Hōei 4, 23rd day of the 11th month): An eruption of Mt . Fuji; the cinders and ash fell like rain in Izu, Kai, Sagami, and Musashi . This eruption was remarkable in that it spread a vast amount of volcanic ash and scoria over a region as far away as Edo . </Li> <P> Sixteen eruptions of New Fuji have been recorded since 781 . Many of the eruptions occurred in the Heian era, with twelve eruptions between 800 and 1083 . Sometimes inactive periods between eruptions lasted for hundreds of years, as in the period between 1083 and 1511, when no eruptions were recorded for over 400 years . At present, there have been no eruptions since the Hoei eruption in 1707--1708, around 300 years ago . </P> <P> Scientists study the activity of the magma rising by measuring CO emissions in the deeper parts of the volcano . Studies from before the Tohoku earthquake show the CO emissions below 5 gCO / m / day, which is the detection limit . If the emissions rise above 5 gCO / m / day then seismic activity is occurring and an eruption could possibly take place . According to a five - stage evolutionary model for the release of volcanic gas, Mt . Fuji would be considered stage I. Magma is at a considerable 10 km (6.2 mi) depth and no emissions of gasses can be observed regularly . </P>

When is the last time mt fuji erupted