Dormant Volcanoes - Japan



Some active volcanoes have been dormant for hundreds or thousands of years..  They created beautiful overview of their mountain ranges and forests around the vents.  However, Japanese historians recorded volcanic hazards in reports, songs, and poems when they erupted.    


Mt. Fuji

Mt. Fuji has the highest elevation in Japan, and is considered as a symbol of spaciousness, apotheosis, and dynamism.  There are some scars of the eruptions on the surface of Mt. Fuji.  The most intensive volcanic activities occurred between 9th and 11th Centuries (1), and the rmost recent eruption occurred in 1708, and was 5 in the Volcanic Explosivity Index (VEI).  The eruptions in the early centuries were composed a poem or reported in books such as Manyoshu and Nihon Goki.  Also, these books describes volcanic hazards such as laha and ash fall during the eruption, and the ash fall reached to Edo a former name of Tokyo by the Hoei eruption in 1707.    


Fuji     Photo







Photo by Chip Clark, Smisonian Institution (Courtsey of Robert Simmons)


Fuji      Photo







Photo by Lee Siebert, 1970 (Smisonian Institution)






Hoei Eruption of Mt. Fuji

The most recent eruption of Mt. Fuji was in 1707.  The map below shows that the ash traveled to east and covered whole area of Tokyo, Chiba, and Kanagawa during the erupted (2).  Areas that were located closer from the vent recieved approximetly 300 cm ash deposit, while areas that were located far from the vent obtained no or a few centimeters of ash deposit.  The eruption mainly produced pyroclastic flow, ash fall, and laha as volcanic hazards.  Before the eruption, there were a lot of small villages and a couple of big towns near Mt. Fuji.  However, a number of houses were burned, and many villages were destroyed.  For example, villages in Kanagawa (southeast on the map) seriously damaged on flumes by laha, and the laha frequently occurred for several years after the eruption (3).  Also, a large area of agricultural land was damaged by ash fall.  During the eruption, people wrote a song to describe the volcanic hazard, like "Even going back to wind and grind it and this, You know too well know the cough Hokata" (1).  


Map of ash downfall from Wikipedia



(1)  Kazuaki, Ito.  "The classical view of the mountain erupted."  Prevention newsletter 235.  2008. 

(2)  Smithsonian National Musium of National History. "Sakra-jima." Global Volcanism Program. 

(3)  Volcanic-ash-downfall map of Mt. Fuji Hoei Eruption.  Online image.  Wikipedia.  March 21, 2006. 


(4)  Hitomi, S., Kimio, I., Masato, K., and Yoko, T.  "Distribution of sediments after the 1707 Hoei eruption of Fuji Volcano in center

          Japan, base on histrical document."  Rekishijishin.  Vol. 18.  2002.  Page 133-147.