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Smith Island

Sumisujima

Caldera · Japan · 136m

Wave erosion has exposed the spectacular stratigraphy of Sumisujima, a steep-sided pinnacle that is a remnant of the outer southern flank of a submarine caldera 6-9 km wide. Intrusive rocks, dikes, tephra layers, and breccias are visible in this view of the eastern side of the pinnacle. Submarine eruptions have been reported from a number of locations near here, the last of which occurred in 1916. Water discoloration has been frequently observed nearby since the 1970s.
Wave erosion has exposed the spectacular stratigraphy of Sumisujima, a steep-sided pinnacle that is a remnant of the outer southern flank of a submarine caldera 6-9 km wide. Intrusive rocks, dikes, tephra layers, and breccias are visible in this view of the eastern side of the pinnacle. Submarine eruptions have been reported from a number of locations near here, the last of which occurred in 1916. Water discoloration has been frequently observed nearby since the 1970s. · Photo: Copyrighted photo by Kenichiro Tani, 2002 (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
Caldera
Country
Japan
Region
Northwestern Pacific Volcanic Regions / Izu Volcanic Arc
Elevation
136m
Coordinates
31.440, 140.051
Last eruption
1916
Tectonic setting
Subduction zone / Oceanic crust (< 15 km)
Landform
Caldera
Major rock type
Dacite
Geological summary

Sumisujima (also known as Smith Rocks) is a steep-sided basaltic pinnacle that forms part of the outer southern flank of a 8-9 km submarine caldera that truncates a 20-km-wide seamount. The caldera was formed between about 60,000 and 30,000 years ago. The Shirane dacitic central cone, 3 km wide and 800 m high, rises to within 8 m of the ocean surface in the eastern side of the caldera, whose 600-700 m walls and outer flanks expose basaltic, andesitic, and rhyolitic rocks. Two large submarine cones, Sumisu Knolls No. 1 and 2, lie west of the caldera. Submarine eruptions have been reported from a number of locations near Sumisujima, the last of which occurred in 1916. Water discoloration has frequently been observed since the 1970's. In October 1992 a 6-km-long zone of discolored water was seen extending from the shallow Shirane rock mass near the eastern rim of the caldera, which rises to within 7 m of the ocean surface and is the youngest feature of the volcanic complex.

From Wikipedia

Sumisu Island is a volcanic, deserted island located in the Philippine Sea approximately 110 kilometres (68 mi) off the coast of Aogashima, near the southern end of the Izu archipelago, Japan. Sumisu-tō is administratively part of Tokyo Metropolis.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
1672~1707 · 1 eruptions · max VEI 01848~1883 · 2 eruptions · max VEI 21883~1918 · 1 eruptions · max VEI 01954~1989 · 4 eruptions · max VEI 01989~2024 · 17 eruptions · max VEI 016721742184819181989

Detailed timeline

  1. 2024VEI ?Observed
    2024-09-18 – 2024-10-05
  2. 2005VEI 0Geological estimate
    2005-03-08 – 2005-03-08
  3. 2003VEI 0Geological estimate
    2003-11-06 – 2003-11-06
  4. 2002VEI 0Geological estimate
    2002-09-04 – 2002-09-04
  5. 2001VEI 0Geological estimate
    2001-10-31 – 2002-02-28
  6. 2000VEI 0Geological estimate
    2000-10-30 – 2000-10-30
  7. 1998VEI 0Geological estimate
    1998-10-27 – 1999-01-13
  8. 1997VEI 0Geological estimate
    1997-11-21 – 1997-11-21
  9. 1996VEI 0Geological estimate
    1996-01-22 – 1996-01-22
  10. 1995VEI 0Geological estimate
    1995-07-05 – 1995-07-07
  11. 1994VEI 0Geological estimate
    1994-01-17 – 1994-01-17
  12. 1994VEI 0Geological estimate
    1994-07-27 – 1994-07-27
  13. 1993VEI 0Geological estimate
    1993-09-08 – 1993-09-10
  14. 1992VEI 0Geological estimate
    1992-08-05 – 1992-10-07
    Shirane (7.5 km NE of Smith Rocks)
  15. 1991VEI 0Geological estimate
    1991-11-05 – 1991-11-05
  16. 1989VEI 0Geological estimate
    1989-01-18 – 1989-01-18
  17. 1989VEI 0Geological estimate
    1989-07-18 – 1989-07-18
  18. 1977VEI 0Geological estimate
    1977-10-16 – 1977-10-16
  19. 1976VEI 0Geological estimate
    1976-08-16 – 1976-08-16
  20. 1975VEI 0Geological estimate
    1975-08-13 – 1975-09-26
  21. 1974VEI 0Geological estimate
    1974-07-06 – 1974-07-06
  22. 1916VEI 0Observed
    1916-06-21 – Ongoing
    Just west of Smith Rock
  23. 1873VEI 0Geological estimate
    1873 – Ongoing
    31.28 N 139.92 E
  24. 1870VEI 2Observed
    1870-05 – Ongoing
    18 km SW of Smith Rock
  25. 1672VEI 0Geological estimate
    1672 – Ongoing
    31.58 N 140.25 E

External links

⚠ For reference only. Not for emergency response.