Chokai Volcano

Updated: Apr 29, 2025 08:13 GMT - refresh

stratovolcanoes

Honshu, Japan, 39.1°N / 140.05°E

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Summit height: 2233 m / 7,326 ft

Current status: normal or dormant (1 out of 5)

Chokai volcano

Chokai or Chokaisan volcano (鳥海山 Chōkai-san) is the largest volcano of NE Honshu.
It is a massive stratovolcano with a broad conical profile which is why it is called locally Akita-Fuji or Dewa-Fuji. Its height measures from the WNW elongated 15x20 km base about 2000 m.
The volcano is located about 60 km west behind the main volcanic front of the Honshu arc and towers above the Japan Sea.
Chokai consists of 2 overlapping volcanoes, the western and older volcano Nishi-Chokai and the younger eastern volcano Higashi-Chokai, forming the 2 distinct peaks. Historic records of eruptions, mostly phreatic explosions, go back to the 6th century AD.

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Chokai webcams / live data | News/Updates | Earthquakes

Typical eruption style: phreatic explosions
Chokai volcano eruptions: March-April 1974: phreatic ash explosions and mud flows
1834: phreatic explosions and mud flows
1821: phreatic explosions
1800-04, 1764 (?), 1740-47, 1738±1 (?), 1735 (?), 1659-63, 1560 (?), 1477 (?), 999 AD (?), 948±1, 939, (915: no eruption, was from Towada volcano), 884 (?), 871, 861 (?), 857 (?), 856 (?), 839 (?), 830, 817 AD ± 7 years, 804-06, 717 (?), 711± 3 years, 610± 18 years (?), 577-78 (?), 573 (?), 450 BC, 650 BC, 1050 BC (?)

Latest nearby earthquakes

Date and Time	Mag / Depth	Distance / Location
Apr 28, 02:47 am (GMT +9)	3.1 17 km	18 km (10.9 mi) to the S	Japan: Northern Yamagata Pref I FELT IT	Info
Apr 28, 02:47 am (GMT +9)	3.0 17 km	18 km (11 mi) to the S	Tottori, 14 km east of Sakata, Yamagata, Japan I FELT IT	Info

View recent quakes

Background

The older Nishi-Chokai volcano suffered flank collapse leaving a large horseshoe-shaped caldera open to the south. Lava domes grew on the caldera floor. A younger stratovolcano grew successively to the east, building Higashi-Chokai from about 20,000 years ago. This volcano, too, partly collapsed about 2600 years ago and left a caldera breached to the north. The collapse produced the voluminous Kisakata debris avalanche, which reached the Pacific coast.

Significant volcanic eruptions: Chokai volcano

In the past 10,000 years, Chokai has had at least 14 confirmed volcanic eruptions, out of which 11 are documented by historical records, while the others can be inferred from geological evidence.
Additionally, there are 18 uncertain or discredited eruptions from Chokai volcano.

The table below lists all known eruptions (date in bold face) of Chokai volcano in historic times and during the past 10,000 years. Updates on the most recent volcanic activity of Chokai can be found on the news page of Chokai volcano.

Date	Note	VEI	Deaths
1974 Mar 1 - Apr 30	E side of Shinzan, W of Kojin-yama Historical obs./docs.	1
1834 Jul 9 - Jul	Historical obs./docs.	2?
1821 May 23	Near Shinzan and Shichiko-zan Historical obs./docs.	2?
1800 Dec - 1804 Jul	Shinzan (foot of Kojin-yama) Historical obs./docs.	2
1801 Aug 14 (eruption 1800 Dec - 1804 Jul)	Historical obs./docs.	2	8	Info
1801 Aug 14: Climbers killed by volcanic ejecta. (reference #9675) Volcanic blocks killed 8 mountain climbers. (reference #12936) Cited references #1412 Simkin, Tom, and Lee Siebert with the collaboration of Russell Blong, Jonathan Dehn, Christopher Newhall, Roland Pool, and Thomas C. Stein (1994): Volcanoes of the World, Second Edition, A Regional Directory, Gazetteer, and Chronology of Volcanism During the Last 10,000 Years, Geoscience Press, Inc., Tucson, Arizona, in association with Smithsonian Institution, Global Volcanism Program, Washington, D.C., p. 164-176. #9675 Siebert, Lee, Tom Simkin, Paul Kimberly (2010): Fatalities & Evacuations, Volcanoes of the World, Third Edition, Geoscience Press, Inc., University of California Press, Smithsonian Institution, Washington, D.C., p. 329-347. #12936 Japan Meteorological Agency and Volcanological Society of Japan (2013): National Catalogue of the Active Volcanoes in Japan (fourth edition, English version). Japan Meteorological Agency. [accessed May 20, 2021] Link Source: NOAA National Centers for Environmental Information (NCEI), Global Significant Earthquake Database. doi:10.7289/V5TD9V7K
?? 1764	Uncertain Eruption	2
1740 Jun - 1747 ?	Small crater at foot of Kojin-yama Historical obs./docs.	2?
?? 1738 Dec 31 ±365 d.	Uncertain Eruption	2
?? 1735	Uncertain Eruption	2
1659 AD Apr - 1663 ±1 y.	Historical obs./docs.	?
?? 1560 AD	Uncertain Eruption	?
?? 1477 AD	Uncertain Eruption	?
?? 999 AD	Uncertain Eruption	?
?? 948 AD Dec 31 ±365 d.	Uncertain Eruption	?
939 AD May 15	Historical obs./docs.	?
915 AD Aug 23 - Sep 1	Discredited Eruption
?? 884 AD Jul 26 - Aug	Uncertain Eruption	?
871 AD May 5	Historical obs./docs.	2
?? 861 AD May	Uncertain Eruption	3
?? 857 AD May	Uncertain Eruption	?
?? 856 AD	Uncertain Eruption	?
?? 839 AD Oct 14	Uncertain Eruption	?
830 AD Jan	Historical obs./docs.	?
817 ±7 y. AD	Historical obs./docs.	?
?? 804 AD - 806	Uncertain Eruption	?
?? 717 AD Jul	Uncertain Eruption	?
711 ±3 y. AD	Historical obs./docs.	?
?? 610 ±18 y. AD	Uncertain Eruption	?
?? 577 AD Dec 1 ±30 d. - 578 Jul 15 ±45 d.	Uncertain Eruption	?
?? 573 AD Mar	Uncertain Eruption	?

Remark:

Our list of volcanic eruptions closely follows the database of eruptions of the Smithsonian's Global Volcanism Project (GVP), the internationally most recognized data source for volcanic eruptions, but also includes significant eruptive episodes or related volcano events. "Volcanic eruptions" are usually to be understood as sequences of individual eruptive episodes that can follow each other, or even overlap (if several vents are involved), and can last many years, decades or even longer. For example, the current activity of Stromboli volcano is understood as a single eruption that has been ongoing since 1934.

Sources: NOAA National Centers for Environmental Information (NCEI), Global Significant Volcanic Eruptions Database. doi:10.7289/V5TD9V7K | Global Volcanism Project / Smithsonian Institution

Eruptions of Chokai volcano

1974 eruption
"After a long period of inactivity (since 1821), Tyokai volcano blew up on 1 March" reads the beginning of a bulletin received by the Smithsonian Institution on 1 April 1974.
The eruption took place in 2 phases, at the beginning of March and at the end of April 1974 and consisted in phreatic explosions generating mud flows at the snow-covered summit of Chokai volcano. It followed 153 years of dormancy. No magma reached the surface, but a very shallow intrusion was the cause of the eruptionn. ...more info

1800-1804 eruption and fatalities
An eruption began at Kojin-yama crater and built a lava dome (Shinzan). The eruption caused fatalities when climbers were killed by ballistic blocks ejected during an explosion in 1801.

Chokai Volcano FAQ

+When was the last eruption of Chokai volcano?

The last confirmed eruption of Chokai occurred in 1974.

+How often does Chokai volcano erupt?

Since 711 AD, Chokai volcano has had at least 11 historically documented eruptions. This means that it erupts on average every 119 years.
Many eruptions of Chokai have lasted more than one year. In total, the volcano has been in eruption during 26 out of 1314 years until now. In other words, Chokai has been active at least one in 50.5 years on average. Note that this value is likely an underestimate, because the known history of eruptions from Chokai is likely incomplete, especially further back in time.

+How active is Chokai volcano at present?

Chokai volcano is occasionally active: Since 1900, it has had one eruption, which occurred in 1974.

+When was the largest eruption of Chokai volcano?

The largest eruption of Chokai volcano in historic times occurred in 1834. It ranks as a strombolian to vulcanian eruption with a magnitude 2 on the VEI (Volcanic Explosivity Index) scale.

Latest satellite images

See also: Sentinel hub | Landsat 8 | NASA FIRMS

Latest satellite images

Chokai Volcano Maps

Below is a selection of maps showing the location and surroundings of the volcano at various resolutions based on aerial-imagery / terrain maps. Feel free to use them for non-commercial purposes on your blog or website as long as you credit them with a link back to this page (click to copy it).