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Mount Iwate

Iwatesan

Complex volcano · Japan · 2038m

Yakushidake (right) forms the summit of Iwatesan, and is a younger cone that was constructed over the eastern rim of NishiIwate caldera, the left-hand peak in this view from the SE. Eruptions have been recorded since the 17th century, mostly from the 500-m-wide summit crater and flank vents.
Yakushidake (right) forms the summit of Iwatesan, and is a younger cone that was constructed over the eastern rim of NishiIwate caldera, the left-hand peak in this view from the SE. Eruptions have been recorded since the 17th century, mostly from the 500-m-wide summit crater and flank vents. · Photo: Photo by Lee Siebert, 1977 (Smithsonian Institution). · Wikimedia Commons
Type
Complex volcano
Country
Japan
Region
Northwestern Pacific Volcanic Regions / Northeast Japan Volcanic Arc
Elevation
2038m
Coordinates
39.853, 141.001
Last eruption
1919
Tectonic setting
Subduction zone / Continental crust (> 25 km)
Landform
Composite
Major rock type
Basalt / Picro-Basalt
Geological summary

Viewed from the east, Iwatesan volcano has a symmetrical profile that invites comparison with Fuji, but on the west an older cone is visible containing an oval-shaped, 1.8 x 3 km caldera. After the growth of Nishi-Iwate volcano beginning about 700,000 years ago, activity migrated eastward to form Higashi-Iwate volcano. Iwate has collapsed seven times during the past 230,000 years, most recently between 739 and 1615 CE. The dominantly basaltic summit cone of Higashi-Iwate volcano, Yakushidake, is truncated by a 500-m-wide crater. It rises well above and buries the eastern rim of the caldera, which is breached by a narrow gorge on the NW. A central cone containing a 500-m-wide crater partially filled by a lake is located in the center of the oval-shaped caldera. A young lava flow from Yakushidake descended into the caldera, and a fresh-looking lava flow from the 1732 eruption traveled down the NE flank.

From Wikipedia

Mount Iwate is a stratovolcano complex in the Ōu Mountains of western Iwate Prefecture, in the Tōhoku region of northern Honshū, Japan. With an elevation of 2,038 metres (6,686 ft), it is the highest in Iwate Prefecture. It is included as one of the 100 famous mountains in Japan, a book composed in 1964 by mountaineer and author Kyūya Fukada. The mountain is on the borders of the municipalities of Hachimantai, Takizawa, and Shizukuishi, west of the prefectural capital of Morioka. Much of the mountain is within the borders of the Towada-Hachimantai National Park. The mountain is also referred to as the "Nanbu Fuji" for its resemblance to Mount Fuji.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
6450 BCE~6171 BCE · 2 eruptions · max VEI ?5891 BCE~5612 BCE · 1 eruptions · max VEI ?5053 BCE~4773 BCE · 2 eruptions · max VEI ?4494 BCE~4214 BCE · 2 eruptions · max VEI 03935 BCE~3655 BCE · 1 eruptions · max VEI ?3376 BCE~3096 BCE · 1 eruptions · max VEI 03096 BCE~2817 BCE · 2 eruptions · max VEI ?2817 BCE~2537 BCE · 1 eruptions · max VEI ?2258 BCE~1979 BCE · 2 eruptions · max VEI ?1699 BCE~1420 BCE · 2 eruptions · max VEI ?1420 BCE~1140 BCE · 2 eruptions · max VEI 3581 BCE~302 BCE · 2 eruptions · max VEI ?22 BCE~257 · 1 eruptions · max VEI ?1096~1375 · 1 eruptions · max VEI 31375~1655 · 1 eruptions · max VEI ?1655~1934 · 6 eruptions · max VEI 36450 BCE4494 BCE2258 BCE302 BCE1655

Detailed timeline

  1. 1934VEI ?Geological estimate
    1934-07 – 1935
  2. 1919VEI 1Observed
    1919-07-15 – 1919-07-15
    W side of Onigajo caldera (O-jigokudani)
  3. 1732VEI 2Observed
    1732-01-22 – 1732-10
    NE flank of Yakushi-dake
  4. 1689VEI 2Geological estimate
    1689-06-22 – Ongoing
  5. 1687VEI 2Geological estimate
    1687-04-14 – 1687-07
  6. 1686VEI 3Observed
    1686-03-26 – 1686-03-27
  7. 1450 (±100 yrs)VEI ?Geological estimate
    1450 – Ongoing
    Nishi-Iwate and Higashi-Iwate
  8. 1300 (±50 yrs)VEI 3Geological estimate
    1300 – Ongoing
    Higashi-Iwate (Myoko-dake)
  9. 150VEI ?Geological estimate
    150 – Ongoing
    Higashi-Iwate
  10. 350 BCEVEI ?Geological estimate
    BCE 350 – Ongoing
    Higashi-Iwate
  11. 450 BCEVEI ?Geological estimate
    BCE 450 – Ongoing
    Nishi-Iwate (O-jigokudani area)
  12. 1150 BCEVEI ?Geological estimate
    BCE 1150 – Ongoing
    Nishi-Iwate
  13. 1250 BCEVEI 3Geological estimate
    BCE 1250 – Ongoing
    Higashi-Iwate
  14. 1500 BCE (±300 yrs)VEI ?Geological estimate
    BCE 1500 – Ongoing
    Higashi-Iwate
  15. 1650 BCEVEI ?Geological estimate
    BCE 1650 – Ongoing
    Nishi-Iwate (O-jigokudani area)
  16. 2000 BCEVEI ?Geological estimate
    BCE 2000 – Ongoing
    Nishi-yama
  17. 2050 BCE (±200 yrs)VEI ?Geological estimate
    BCE 2050 – Ongoing
    Higashi-Iwate
  18. 2700 BCE (±200 yrs)VEI ?Geological estimate
    BCE 2700 – Ongoing
    Higashi-Iwate
  19. 2950 BCE (±50 yrs)VEI ?Geological estimate
    BCE 2950 – Ongoing
    Nishi-Iwate
  20. 3050 BCEVEI ?Geological estimate
    BCE 3050 – Ongoing
    Higashi-Iwate
  21. 3250 BCE (±500 yrs)VEI 0Geological estimate
    BCE 3250 – Ongoing
  22. 3750 BCE (±100 yrs)VEI ?Geological estimate
    BCE 3750 – Ongoing
    Higashi-Iwate
  23. 4350 BCE (±500 yrs)VEI ?Geological estimate
    BCE 4350 – Ongoing
    Higashi-Iwate
  24. 4450 BCE (±500 yrs)VEI 0Geological estimate
    BCE 4450 – Ongoing
    Higashi-Iwate
  25. 4850 BCE (±50 yrs)VEI ?Geological estimate
    BCE 4850 – Ongoing
    Nishi-Iwate
  26. 4900 BCE (±100 yrs)VEI ?Geological estimate
    BCE 4900 – Ongoing
    Higashi-Iwate
  27. 5650 BCE (±50 yrs)VEI ?Geological estimate
    BCE 5650 – Ongoing
    Nishi-Iwate
  28. 6300 BCE (±100 yrs)VEI ?Geological estimate
    BCE 6300 – Ongoing
    Nishi-Iwate
  29. 6450 BCE (±1600 yrs)VEI ?Geological estimate
    BCE 6450 – Ongoing

External links

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