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Izu Ōshima

Izu-Oshima

Stratovolcano · Japan · 746m

A plume rises from the crater of Miharayama on Oshima island. It lies within a 4-km-wide caldera, the rim of which is prominently visible in this aerial photo from the SW. Dark-colored lava flows from the 1986 eruption cover part of the caldera floor. More than 40 cones are located within the caldera and along two parallel rift zones trending NNW-SSE across the island. The port city of Motomachi on the west coast is to the left and the island's airport is at the upper left.
A plume rises from the crater of Miharayama on Oshima island. It lies within a 4-km-wide caldera, the rim of which is prominently visible in this aerial photo from the SW. Dark-colored lava flows from the 1986 eruption cover part of the caldera floor. More than 40 cones are located within the caldera and along two parallel rift zones trending NNW-SSE across the island. The port city of Motomachi on the west coast is to the left and the island's airport is at the upper left. · Photo: Photo by Ichio Moriya (Kanazawa University). · Wikimedia Commons
Type
Stratovolcano
Country
Japan
Region
Northwestern Pacific Volcanic Regions / Izu Volcanic Arc
Elevation
746m
Coordinates
34.724, 139.394
Last eruption
1990
Tectonic setting
Subduction zone / Oceanic crust (< 15 km)
Landform
Composite
Major rock type
Basalt / Picro-Basalt
Geological summary

Izu-Oshima volcano in Sagami Bay, east of the Izu Peninsula, is the northernmost of the Izu Islands. The broad, low stratovolcano forms an 11 x 13 km island constructed over the remnants of three older dissected stratovolcanoes. It is capped by a 4-km-wide caldera with a central cone, Miharayama, that has been the site of numerous recorded eruptions datining back to the 7th century CE. More than 40 cones are located within the caldera and along two parallel rift zones trending NNW-SSE. Although it is a dominantly basaltic volcano, strong explosive activity has occurred at intervals of 100-150 years throughout the past few thousand years. A major eruption in 1986 produced spectacular lava fountains up to 1,600 m high and a 16-km-high eruption column; more than 12,000 people were evacuated from the island.

From Wikipedia

Izu Ōshima is an inhabited volcanic island in the Izu archipelago and borders Sagami Bay and the Pacific Ocean, off the coast of Honshu, Japan, 22 km (14 mi) east of the Izu Peninsula and 36 km (22 mi) southwest of Bōsō Peninsula. As with the other islands in the Izu Island group, Izu Ōshima forms part of the Fuji-Hakone-Izu National Park. Izu Ōshima, at 91.06 km2 (35.16 sq mi) is the largest and closest of Tokyo's outlying islands, which also include the Ogasawara Islands.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
8450 BCE~8102 BCE · 1 eruptions · max VEI ?8102 BCE~7754 BCE · 1 eruptions · max VEI ?7754 BCE~7406 BCE · 1 eruptions · max VEI ?7406 BCE~7058 BCE · 1 eruptions · max VEI ?6710 BCE~6362 BCE · 2 eruptions · max VEI ?6362 BCE~6014 BCE · 1 eruptions · max VEI ?5666 BCE~5318 BCE · 2 eruptions · max VEI ?4970 BCE~4622 BCE · 1 eruptions · max VEI ?4622 BCE~4274 BCE · 1 eruptions · max VEI ?4274 BCE~3926 BCE · 2 eruptions · max VEI ?3926 BCE~3578 BCE · 2 eruptions · max VEI ?2882 BCE~2534 BCE · 1 eruptions · max VEI ?1490 BCE~1142 BCE · 2 eruptions · max VEI ?1142 BCE~794 BCE · 2 eruptions · max VEI 2794 BCE~446 BCE · 1 eruptions · max VEI 3446 BCE~98 BCE · 1 eruptions · max VEI 398 BCE~250 · 1 eruptions · max VEI 3250~598 · 3 eruptions · max VEI 4598~946 · 12 eruptions · max VEI 4946~1294 · 3 eruptions · max VEI 41294~1642 · 13 eruptions · max VEI 41642~1990 · 54 eruptions · max VEI 38450 BCE6014 BCE3230 BCE794 BCE1642

Detailed timeline

  1. 1990VEI 2Observed
    1990-10-04 – 1990-10-04
    Mihara-yama (1987 summit crater)
  2. 1987VEI 2Observed
    1987-11-16 – 1988-01-27
    Mihara-yama
  3. 1986VEI 3Observed
    1986-11-15 – 1986-12-18
    Mihara-yama, N part and NW of caldera
  4. 1974VEI 1Observed
    1974-02-28 – 1974-06-20
    Mihara-yama
  5. 1971VEI 1Observed
    1971-04-05 – 1971-04-05
    Mihara-yama
  6. 1970VEI 1Observed
    1970-01-26 – 1970-01-31
    Mihara-yama
  7. 1970VEI 1Observed
    1970-06-30 – 1970-11-12
    Mihara-yama
  8. 1969VEI 1Observed
    1969-01-19 – 1969-07-16
    Mihara-yama
  9. 1968VEI 1Observed
    1968-01-19 – 1968-01-19
    Mihara-yama
  10. 1968VEI 1Observed
    1968-07-28 – 1968-07-28
    Mihara-yama
  11. 1967VEI 1Observed
    1967-05-16 – 1967-08-16
    Mihara-yama
  12. 1965VEI 1Observed
    1965-11-25 – 1966-06-13
    Mihara-yama
  13. 1962VEI 1Observed
    1962-01-16 – 1965-05-16
    Mihara-yama
  14. 1961VEI ?Geological estimate
    1961-07-02 – Ongoing
    Mihara-yama
  15. 1959VEI 1Observed
    1959-01-16 – 1959-01-16
    Mihara-yama
  16. 1959VEI 1Observed
    1959-10-16 – 1960-11-16
    Mihara-yama
  17. 1958VEI 1Observed
    1958-04-17 – 1958-06-13
    Mihara-yama
  18. 1957VEI 1Observed
    1957-08-16 – 1957-12-16
    Mihara-yama
  19. 1956VEI 1Observed
    1956-01-03 – 1956-01-06
    Mihara-yama
  20. 1956VEI 1Geological estimate
    1956-08-25 – 1956-08-26
    Mihara-yama
  21. 1953VEI 1Observed
    1953-10-05 – 1954-02-08
    Mihara-yama
  22. 1950VEI 2Observed
    1950-07-16 – 1951-06-28
    Mihara-yama, south rim
  23. 1940VEI 1Observed
    1940-08-18 – 1940-08-19
    Mihara-yama
  24. 1939VEI 1Observed
    1939-02 – 1939-02
    Mihara-yama
  25. 1939VEI 1Observed
    1939-09-01 – 1939-09-16
    Mihara-yama
  26. 1938VEI 1Observed
    1938-08-11 – 1938-08-11
    Mihara-yama
  27. 1937VEI 0Observed
    1937-07-17 – 1937-08
    Mihara-yama
  28. 1935VEI 0Observed
    1935-04-26 – 1935-05-06
    Mihara-yama
  29. 1934VEI 0Observed
    1934-04-15 – 1934-04-25
    Mihara-yama
  30. 1934VEI ?Geological estimate
    1934-09 – Ongoing
    Mihara-yama
  31. 1933VEI 0Observed
    1933-10-14 – 1933-11
    Mihara-yama
  32. 1928VEI 2Observed
    1928-08-07 – 1928-08-08
    Mihara-yama
  33. 1922VEI 1Observed
    1922-12-08 – 1923-01-30
    Mihara-yama
  34. 1920VEI ?Geological estimate
    1920 – Ongoing
    Mihara-yama
  35. 1919VEI 0Observed
    1919-05-18 – 1919-12-23
    Mihara-yama
  36. 1915VEI 2Observed
    1915-10-10 – 1915-10-25
    Mihara-yama
  37. 1914VEI 2Observed
    1914-05-15 – 1914-05-26
    Mihara-yama
  38. 1912VEI 1Observed
    1912-02-23 – 1913-01-25
    Mihara-yama
  39. 1910VEI 1Observed
    1910-12 – Ongoing
    Mihara-yama
  40. 1876VEI 2Observed
    1876-12-27 – 1877-02-05
    Mihara-yama
  41. 1870VEI 2Observed
    1870 – Ongoing
    Mihara-yama
  42. 1868VEI ?Geological estimate
    1868-12-31 – Ongoing
    Mihara-yama
  43. 1846VEI 2Observed
    1846 – Ongoing
    Mihara-yama
  44. 1837VEI 2Geological estimate
    1837 – 1838
    Mihara-yama
  45. 1827VEI ?Geological estimate
    1827 – Ongoing
    Mihara-yama
  46. 1822VEI 2Observed
    1822 – 1824
    Mihara-yama
  47. 1821VEI 3Geological estimate
    1821 – Ongoing
  48. 1803VEI 2Observed
    1803-09-26 – 1803-11-14
    Mihara-yama
  49. 1792VEI 2Observed
    1792 – Ongoing
    Mihara-yama
  50. 1789VEI 2Observed
    1789 – Ongoing
    Mihara-yama
  51. 1783VEI 2Observed
    1783 – 1786
    Mihara-yama
  52. 1777VEI 3Observed
    1777-08-31 – 1779
    Mihara-yama & flanks
  53. 1695VEI ?Observed
    1695-04-12 – Ongoing
  54. 1684VEI 3Observed
    1684-02-14 – 1690
  55. 1637VEI ?Observed
    1637-08-26 – 1638-04
  56. 1634VEI ?Observed
    1634 – Ongoing
  57. 1623VEI ?Observed
    1623 – Ongoing
  58. 1612VEI ?Observed
    1612-10-15 – Ongoing
  59. 1600VEI ?Observed
    1600-10 – Ongoing
  60. 1552VEI 3Observed
    1552-10-07 – 1552-10-15
  61. 1471VEI 2Geological estimate
    1471 – Ongoing
  62. 1442VEI ?Observed
    1442-08 – 1443
  63. 1421VEI 4Observed
    1421-05-14 – Ongoing
    Summit, S flank
  64. 1416VEI 2Observed
    1416-09-02 – 1417
  65. 1415VEI ?Observed
    1415-05-21 – Ongoing
  66. 1338VEI 3Observed
    1338-09-15 – 1338-11-15
  67. 1307VEI 3Geological estimate
    1307 – Ongoing
    NW flank
  68. 1245VEI 1Geological estimate
    1245 – Ongoing
  69. 1183VEI 4Geological estimate
    1183 – Ongoing
  70. 1112VEI ?Geological estimate
    1112-11-18 – 1112-12-26
  71. 936VEI ?Geological estimate
    936 – Ongoing
  72. 886VEI 4Observed
    886-06-29 – Ongoing
  73. 854VEI 4Observed
    854-09-14 – 856
  74. 838VEI 3Observed
    838-08 – Ongoing
    Summit, SE flank
  75. 822VEI 3Geological estimate
    822 – Ongoing
  76. 713VEI 3Geological estimate
    713 – Ongoing
    Summit, N & S flanks
  77. 700VEI 3Geological estimate
    700 – Ongoing
  78. 684VEI ?Observed
    684-11-29 – Ongoing
  79. 680VEI 4Observed
    680 – 681-03-26
  80. 654VEI 3Observed
    654 – Ongoing
  81. 625VEI 3Geological estimate
    625 – Ongoing
  82. 600VEI 3Geological estimate
    600 – Ongoing
  83. 580VEI 3Geological estimate
    580 – Ongoing
  84. 340 (±200 yrs)VEI 4Geological estimate
    340 – Ongoing
    Summit and east flank
  85. 250 (±100 yrs)VEI 3Geological estimate
    250 – Ongoing
  86. 150 (±50 yrs)VEI 3Geological estimate
    150 – Ongoing
  87. 150 BCEVEI 3Geological estimate
    BCE 150 – Ongoing
  88. 600 BCE (±500 yrs)VEI 3Geological estimate
    BCE 600 – Ongoing
  89. 900 BCE (±100 yrs)VEI 2Geological estimate
    BCE 900 – Ongoing
    SE flank
  90. 1050 BCE (±200 yrs)VEI ?Geological estimate
    BCE 1050 – Ongoing
  91. 1200 BCEVEI ?Geological estimate
    BCE 1200 – Ongoing
  92. 1450 BCEVEI ?Geological estimate
    BCE 1450 – Ongoing
  93. 2550 BCEVEI ?Geological estimate
    BCE 2550 – Ongoing
  94. 3650 BCEVEI ?Geological estimate
    BCE 3650 – Ongoing
  95. 3750 BCEVEI ?Geological estimate
    BCE 3750 – Ongoing
  96. 4000 BCE (±300 yrs)VEI ?Geological estimate
    BCE 4000 – Ongoing
  97. 4250 BCEVEI ?Geological estimate
    BCE 4250 – Ongoing
  98. 4450 BCEVEI ?Geological estimate
    BCE 4450 – Ongoing
  99. 4920 BCE (±500 yrs)VEI ?Geological estimate
    BCE 4920 – Ongoing
  100. 5450 BCE (±75 yrs)VEI ?Geological estimate
    BCE 5450 – Ongoing
  101. 5550 BCEVEI ?Geological estimate
    BCE 5550 – Ongoing
  102. 6050 BCE (±500 yrs)VEI ?Geological estimate
    BCE 6050 – Ongoing
  103. 6550 BCEVEI ?Geological estimate
    BCE 6550 – Ongoing
  104. 6650 BCEVEI ?Geological estimate
    BCE 6650 – Ongoing
  105. 7150 BCE (±500 yrs)VEI ?Geological estimate
    BCE 7150 – Ongoing
  106. 7650 BCEVEI ?Geological estimate
    BCE 7650 – Ongoing
  107. 8050 BCE (±500 yrs)VEI ?Geological estimate
    BCE 8050 – Ongoing
  108. 8450 BCEVEI ?Geological estimate
    BCE 8450 – Ongoing

External links

⚠ For reference only. Not for emergency response.