Iwakisan

Photo of this volcano
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 40.656°N
  • 140.303°E

  • 1625 m
    5330 ft

  • 283270
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Iwakisan.

The Global Volcanism Program has no Weekly Reports available for Iwakisan.

The Global Volcanism Program has no Bulletin Reports available for Iwakisan.

Eruptive History


Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1863 Mar 23 Unknown Confirmed 1 Historical Observations
[ 1856 May 20 ] [ Unknown ] Uncertain 2  
[ 1848 Jan 18 ] [ Unknown ] Uncertain 2  
1845 Apr 4 Unknown Confirmed 2 Historical Observations
1844 Apr 7 Unknown Confirmed 2 Historical Observations Summit and south flank?
[ 1833 Apr 11 ] [ Unknown ] Uncertain 2  
[ 1807 Mar 31 ] [ Unknown ] Uncertain 2  
[ 1800 May 11 ] [ Unknown ] Uncertain 2  
[ 1794 Apr 3 ] [ Unknown ] Uncertain 2  
[ 1793 Apr 2 ] [ Unknown ] Uncertain 2  
1790 Oct 9 Unknown Confirmed 2 Historical Observations
[ 1783 Dec 3 ] [ Unknown ] Uncertain 2  
1782 Dec 1 ± 30 days 1783 Mar 12 Confirmed 2 Historical Observations
[ 1782 Apr 12 ] [ Unknown ] Uncertain 2   South flank
[ 1769 ] [ Unknown ] Uncertain 2  
[ 1709 Apr 23 ] [ Unknown ] Uncertain 2  
[ 1694 Jun 19 ] [ Unknown ] Uncertain 2  
[ 1672 Jul 12 ] [ 1672 Jul 28 ] Uncertain 2  
1618 Jan 31 Unknown Confirmed 2 Historical Observations
[ 1605 Apr 10 ] [ Unknown ] Uncertain 2  
1604 Feb 7 Unknown Confirmed 3 Historical Observations Torinoumi
1600 Jul 23 1600 Jul 25 Confirmed 2 Historical Observations Torinoumi
1600 Feb 22 Unknown Confirmed 2 Historical Observations Torinoumi
[ 1597 Jun 13 ] [ Unknown ] Uncertain 2  
[ 1597 Jan ] [ Unknown ] Uncertain 2  
0550 BCE ± 500 years Unknown Confirmed   Tephrochronology Torinoumi lava dome
1050 BCE (?) Unknown Confirmed   Tephrochronology Summit and central lava dome
4050 BCE (?) Unknown Confirmed   Tephrochronology West summit lava dome
8050 BCE (?) Unknown Confirmed   Potassium-Argon Torinoumi lava dome

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Photo Gallery


The irregular summit lava dome filling the central crater of Iwaki volcano forms the high point in this view of the SE side of the volcano. Chokai-san is the rounded peak on the left. The summit lava dome is flanked by six explosion craters. Debris-avalanche deposits from repeated collapse of the summit and flanks surround the volcano on all sides. Historical eruptions have been reported since 1597 and have consisted primarily of small-to-moderate phreatic explosions.

Copyrighted photo by Shingo Takeuchi (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/).
See title for photo information.
Snow-capped Iwaki stratovolcano rises above farmlands below its SE flank. The peak at the left side of the summit is Chokai-san. Iwaki volcano, symmetrical on all but its western flanks, has been called the Fuji-san of the Tsugaru district. The 2-km-wide summit crater is filled by a lava dome that forms the high point of the volcano. Historical eruptions have been reported since 1597 and have consisted primarily of small-to-moderate phreatic explosions.

Copyrighted photo by Yoshihiro Ishizuka (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/).
See title for photo information.

Smithsonian Sample Collections Database


The following 2 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections. Catalog number links will open a window with more information.

Catalog Number Sample Description
NMNH 101496 Unidentified
NMNH 101497 Dacite

Affiliated Sites