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Mount Zaō

Zaozan [Zaosan]

Complex volcano · Japan · 1841m

Okama crater of Goryudake within the Zaozan volcanic complex is shown here from the E. The 360-m-wide lake is about 60 m deep and is the site of many recorded eruptions. White mud deposited on the lake floor is periodically disturbed by gas emission, changing the color of the water.
Okama crater of Goryudake within the Zaozan volcanic complex is shown here from the E. The 360-m-wide lake is about 60 m deep and is the site of many recorded eruptions. White mud deposited on the lake floor is periodically disturbed by gas emission, changing the color of the water. · Photo: Copyrighted photo by Yoshihisa Kawanabe (Japanese Quaternary Volcanoes database, RIODB, http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/index.htm and Geol Surv Japan, AIST, http://www.gsj.jp/). · Wikimedia Commons
Type
Complex volcano
Country
Japan
Region
Northwestern Pacific Volcanic Regions / Northeast Japan Volcanic Arc
Elevation
1841m
Coordinates
38.144, 140.440
Last eruption
1940
Tectonic setting
Subduction zone / Continental crust (> 25 km)
Landform
Composite
Major rock type
Andesite / Basaltic Andesite
Geological summary

The Zaozan (or Zaosan) volcano group consists of a complex cluster of stratovolcanoes in north-central Honshu about 40 km W of Sendai Bay. The Pleistocene Ryuzan volcano forms the western group (Nishi-Zao), and Byobu and Fubo volcanoes form the southern group (Minami-Zao). The complex was constructed over granitic basement rocks thus has a relatively small volume. The 7 km3 Zaozan volcano proper forms the central group (Chuo-Zao), a complex topped by several lava domes and the Goshikidake tuff cone, aligned NW-SE. Several episodes of edifice collapse produced debris avalanches during the Pleistocene. Goshikidake contains the active Okama crater, filled with a colorful, strongly acidic crater lake; it has been the source of most of the frequent eruptions recorded since the 8th century CE.

From Wikipedia

The Zaō Mountains , commonly called Mount Zaō, are a complex cluster of stratovolcanoes on the border between Yamagata Prefecture and Miyagi Prefecture in Japan. The central volcano includes several lava domes and a tuff cone, Goshiki-dake, which contains a crater lake named "Okama". Also known as the "Five Color Pond" because it changes color depending on the weather, it lies in a crater formed by a volcanic eruption in the 1720s. The lake is 360 metres (1,200 ft) in diameter and 60 m (200 ft) deep, and is one of the main tourist attractions in the area.

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Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
7600 BCE~7282 BCE · 1 eruptions · max VEI ?5692 BCE~5374 BCE · 2 eruptions · max VEI ?4420 BCE~4102 BCE · 1 eruptions · max VEI ?4102 BCE~3784 BCE · 1 eruptions · max VEI ?3466 BCE~3148 BCE · 1 eruptions · max VEI ?2830 BCE~2512 BCE · 1 eruptions · max VEI ?2512 BCE~2194 BCE · 1 eruptions · max VEI ?2194 BCE~1876 BCE · 1 eruptions · max VEI ?1876 BCE~1558 BCE · 1 eruptions · max VEI ?32~350 · 1 eruptions · max VEI 4668~986 · 2 eruptions · max VEI 3986~1304 · 3 eruptions · max VEI 31304~1622 · 4 eruptions · max VEI 31622~1940 · 31 eruptions · max VEI 37600 BCE5374 BCE2830 BCE604 BCE1622

Detailed timeline

  1. 1940VEI 1Observed
    1940-05-18 – 1940-05-18
    Okama
  2. 1939VEI 1Geological estimate
    1939-07 – Ongoing
    Okama
  3. 1927VEI 1Geological estimate
    1927 – Ongoing
    Okama
  4. 1905VEI 1Observed
    1905 – Ongoing
    Okama
  5. 1897VEI 1Geological estimate
    1897-01-14 – 1897-01-14
    Okama
  6. 1896VEI 1Observed
    1896-03-08 – 1896-03-08
    Okama
  7. 1896VEI 1Geological estimate
    1896-09-01 – Ongoing
    Okama
  8. 1895VEI 1Observed
    1895-02-15 – 1895-03-22
    Okama
  9. 1895VEI 2Observed
    1895-08-22 – 1895-09-28
    Okama
  10. 1894VEI 2Observed
    1894-07-03 – 1894-07-03
    Okama
  11. 1890VEI 1Geological estimate
    1890 – Ongoing
    Okama
  12. 1873VEI 1Observed
    1873-08 – 1873-09
    Okama
  13. 1867VEI 2Observed
    1867-10-21 – Ongoing
    Okama
  14. 1833VEI 2Observed
    1833 – Ongoing
    Okama
  15. 1831VEI 2Observed
    1831-11-22 – Ongoing
    Okama
  16. 1830VEI 2Observed
    1830 – Ongoing
    Okama
  17. 1822VEI ?Observed
    1822-05-01 – Ongoing
  18. 1821VEI 2Observed
    1821-01-27 – 1821-05-01
    Okama
  19. 1809VEI 2Observed
    1809-06-12 – 1809-12-29
    Okama
  20. 1806VEI 2Observed
    1806-07-12 – Ongoing
    Okama
  21. 1804VEI 2Observed
    1804-05 – Ongoing
    Okama
  22. 1796VEI 2Observed
    1796-03-24 – Ongoing
    Okama
  23. 1794VEI 2Observed
    1794-09-22 – 1794-12
    SE side of Okama
  24. 1694VEI 2Observed
    1694-05-29 – 1694-08-30
    Okama
  25. 1670VEI 2Observed
    1670-04-26 – 1670-09-26
    Okama
  26. 1669VEI 3Observed
    1669 – Ongoing
    Okama
  27. 1668VEI 2Observed
    1668-08 – Ongoing
    Okama
  28. 1641VEI 2Observed
    1641 – Ongoing
    Okama
  29. 1630VEI 2Observed
    1630 – Ongoing
    Okama
  30. 1623VEI 3Observed
    1623-05-15 – 1624-11-15
    Okama
  31. 1622VEI 2Observed
    1622 – Ongoing
    Okama
  32. 1620VEI 2Observed
    1620 – Ongoing
    Okama
  33. 1400 (±100 yrs)VEI 3Geological estimate
    1400 – Ongoing
    Goshiki-dake area
  34. 1350VEI 2Geological estimate
    1350 – Ongoing
    Okama
  35. 1331VEI 2Geological estimate
    1331 – 1333
    Okama
  36. 1230VEI 2Observed
    1230-11-29 – Ongoing
    Okama
  37. 1227VEI 3Observed
    1227-10 – Ongoing
    Okama
  38. 1183VEI 2Observed
    1183-05-28 – Ongoing
    Okama
  39. 884VEI 3Observed
    884 – Ongoing
    Okama
  40. 773VEI ?Geological estimate
    773-11 – Ongoing
    Okama
  41. 300 (±200 yrs)VEI 4Geological estimate
    300 – Ongoing
    Goshiki-dake area
  42. 1600 BCEVEI ?Geological estimate
    BCE 1600 – Ongoing
    Goshiki-dake
  43. 2000 BCE (±500 yrs)VEI ?Geological estimate
    BCE 2000 – Ongoing
    Goshiki-dake
  44. 2300 BCE (±75 yrs)VEI ?Geological estimate
    BCE 2300 – Ongoing
    Goshiki-dake area
  45. 2600 BCE (±200 yrs)VEI ?Geological estimate
    BCE 2600 – Ongoing
    Goshiki-dake area
  46. 3350 BCE (±50 yrs)VEI ?Geological estimate
    BCE 3350 – Ongoing
    Goshiki-dake area
  47. 3850 BCE (±200 yrs)VEI ?Geological estimate
    BCE 3850 – Ongoing
    Goshiki-dake area
  48. 4150 BCE (±200 yrs)VEI ?Geological estimate
    BCE 4150 – Ongoing
    Goshiki-dake area
  49. 5500 BCEVEI ?Geological estimate
    BCE 5500 – Ongoing
    Goshiki-dake area
  50. 5600 BCEVEI ?Geological estimate
    BCE 5600 – Ongoing
    Goshiki-dake
  51. 7600 BCEVEI ?Geological estimate
    BCE 7600 – Ongoing
    Goshiki-dake area

External links

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