April 11, 1781 Eruption of Aira

Name: April 11, 1781 Eruption of Aira
Start: 1781-04-11
Location: Aira, Japan

April 11, 1781 · VEI 4 · 38 deaths

Aira in Japan erupted on April 11, 1781 with a Volcanic Explosivity Index of 4. The eruption killed 38 people, counting its secondary effects. It caused a tsunami.

Where it erupted

Aira, Japan, with its other significant eruptions.

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The eruption

Date: April 11, 1781
Volcano: Aira, stratovolcano
Country: Japan
Volcanic Explosivity Index: 4, large (eruption column 10 to 25 km)
Killed by: Waves or tsunami
Tsunami: Yes: the tsunami it caused
Location: 31.577° N, 130.659° E

The toll

Deaths: 23; 38 with the tsunamis, mudflows and other effects it caused
Damage: Limited (under about $1 million) with the tsunamis, mudflows and other effects it caused

Where the literature gives no number, NCEI records a description on a scale of 1 to 4, printed here in its words. Damage is in millions of US dollars of the year of the event, not adjusted for inflation.

What the record says

NCEI’s account, from the sources it cites.

Reference #9675:

1781, April 11. Tsunami upset 3 boats, drowning 14 men and 1 woman. Koto reports 23 sightseers killed in 1781 by paroxysmal outburst.

Reference #2060:

Many people went out daily in boats to see the remarkable spectacle displayed by submarine eruptions near the present west coast of the island, where on April 21 [11], 1781, one of the vessels was hurled up by a paroxysmal outburst, killing

twenty-three of the sight-seers.

Reference #1686:

One of the latter eruptions, on 9 September 1780, generated

waves up to 6 m in height; in another, on 11 April 1781, three boats were overturned and 15 people were drowned (OMORI, 1914, pp. 66-67).

Reference #414:

1781, April 11. An explosion of the Sakurajima volcano caused a tsunami in Kagoshima Bay (Kyushu Island)...According to Kuno (1962), in November 1779, several small islands were formed off the northeastern coast of Sakurajima Island as a result of underwater eruptions and the elevation of the bottom. Underwater eruptions recurred several times before, accompanied by tsunamis, until early in 1782.

Other significant eruptions of Aira

Every eruption in 1781 The 1700s Aira Earthquakes near Aira This day in weather history

Sources

Volcanoes and significant eruptions from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. Volcano numbers are the Smithsonian Institution’s Global Volcanism Program’s. NCEI event 859.