Hōei eruption of Mount Fuji

Map of volcanic ash fall during the Hoei eruption
Mount Fuji, showing the Hōei crater

The Hōei Eruption of Mount Fuji (宝永大噴火 Hōei dai funka) started on 16 December 1707 (23rd day of the 11th month of the year Hōei 4) and ended about 1 January 1708 (9th day of the 12th month of the year Hōei 4) during the Edo period.[1] Although it brought no lava flow, the Hōei eruption released some 800 million cubic metres (28×10^9 cu ft) of volcanic ash, which spread over vast areas around the volcano, even reaching Edo almost 100 kilometres (60 mi) away. Cinders and ash fell like rain in Izu, Kai, Sagami, and Musashi provinces.[2] In Edo, the volcanic ash was several centimetres thick.[3] The eruption is rated a 5 on the Volcanic Explosivity Index.[4]

The eruption occurred on Mount Fuji's east–north-east flank and formed three new volcanic vents, named No. 1, No. 2, and No. 3 Hōei vents. The catastrophe developed over the course of several days; an initial earthquake and explosion of cinders and ash was followed some days later with the more forceful ejections of rocks and stones.[5] Mount Fuji has not erupted since.

Hokusai's One Hundred Views of Mount Fuji includes an image of the small crater which developed from a secondary eruption site on the southwestern slope. This was called Mount Hōei, because the eruption occurred in the fourth year of Hōei.[5]

Today the crater can be visited from Fujinomiya Trail or Gotemba Trail of Mount Fuji.

Secondary disasters

In the year following the Hōei eruption, a secondary disaster occurred when the Sakawa flooded due to sediment build-up resulting from the ash fall.

Volcanic sands fell and widely covered the cultivated fields east of Mount Fuji. To recover the fields farmers cast volcanic products out to dumping-grounds and made sand piles. The rain washed sand piles from the dumping grounds away to the rivers again and again and made some of the rivers shallower, especially into the Sakawa, into which huge volumes of ash fell, resulting in temporary dams. Heavy rainfall on 7–8 August 1708, the year following the Hōei eruption, caused an avalanche of volcanic ash and mud and broke the dams, flooding the Ashigara plain.

See also

Notes

  1. ↑ Shizuoka University page
  2. ↑ Titsingh, Isaac. (1834). Annales des empereurs du japon, p. 416.
  3. ↑ Archived March 25, 2011 at the Wayback Machine
  4. ↑ "Fuji — Eruption History". Global Volcanism Program. Smithsonian Institution. Retrieved 10 August 2013.
  5. 1 2 Smith, Henry. (1988). Hokusai: One Hundred Views of Mt. Fuji. p. 197.

References

External links

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