Kikai Caldera

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Kikai Caldera
Kikai Caldera Relief Map, SRTM, English.jpg
Highest point
Peak Mount Iō (Iōjima) (Iōjima, Ōsumi Islands, Japan)
Elevation 704 m (2,310 ft)
Length 17 km (11 mi) NS
Width 20 km (12 mi) EW
Country Japan
State Kagoshima Prefecture
Region Ōsumi Islands
District Kagoshima District
Municipality Mishima
Age of rock 6,300 to 95,000 years ago

Kikai Caldera (鬼界カルデラ, Kikai karudera) is a massive, mostly submerged caldera up to 19 kilometres (12 mi) in diameter in the Ōsumi Islands of Kagoshima Prefecture, Japan. It is the remains of the ancient eruption of a gigantic volcano. Its geographic coordinates are: Latitude (dd.) 30.79 and Longitude (dd.) 130.31[1]

Kikai Caldera was the source of the Akahoya eruption, one of the largest eruptions during the Holocene (10,000 years ago to present). About 6,300 years ago, pyroclastic flows from that eruption reached the coast of southern Kyūshū up to 100 km (62 mi) away, and ash fell as far as Hokkaidō. The eruption produced about 150 km³ of tephra,[2] giving it a Volcanic Explosivity Index of 7[3] and making it one of the most explosive in the last 10,000 years, ranking alongside Santorini, Changbaishan, Crater Lake, Kurile Lake and Tambora.[4]

Kikai is still an active volcano. Minor eruptions occur frequently on Mount Iō (硫黄岳, Iō-dake), one of the post-caldera subaerial volcanic peaks on Iōjima (硫黄島, Iō-jima). Iōjima is one of three volcanic islands, two of which lie on the caldera rim. The most recent eruptions occurred in 2013. On June 4, 2013, weak tremors were recorded. Shortly after, eruptions began and continued off-and-on for several hours. Due to this activity, an ash cloud formed and moved west. The Japan Meteorological Agency (JMA) raised the Alert Level from 1-2 (on a scale of 5) and released a warning for potentially hazardous conditions both on the leeward side of the island and the area within 1km from the summit.[5]

Further reading[edit]

  • Machida, Hiroshi; Sugiyama, Shinji (2002). "The impact of the Kikai-Akahoya explosive eruptions on human societies". In Grattan, John; Torrence Robin (Ed.). Natural Disasters and Cultural Change. London: Routledge. pp. 313–346. ISBN 0-415-21696-6. 

See also[edit]


  1. ^ "Kikai | Volcano World | Oregon State University". Retrieved 2017-04-11. 
  2. ^ Kikai - Eruptive history, Global Volcanism Program. Smithsonian Institution.
  3. ^ Johnston, Eric, "Latest volcano show: Shinmoe", Japan Times, 1 March 2011, p. 3.
  4. ^ "Large Volcano Explocivity Index". Countries of the World. Retrieved 2014-04-24. 
  5. ^ "Global Volcanism Program | Kikai". Retrieved 2017-04-07. 

External links[edit]