September 9, 1780 Tsunami: SW. Kyushu Island, Japan

Name: September 9, 1780 Tsunami: SW. Kyushu Island, Japan
Start: 1780-09-09
Location: SW. Kyushu Island, Japan

September 9, 1780 · 6 m · Definite tsunami

A tsunami caused by a volcano began at SW. Kyushu Island, Japan on September 9, 1780. The water rose as high as 6 meters. Its effects were recorded at 2 places.

Where the waves reached

The source (white) and every runup with a place, colored by the water height recorded there. A ring is a runup NCEI marks doubtful.

Under 1 m
1 to 3 m
3 to 10 m
10 to 30 m
30 m and more
Height not recorded

Tsunami warnings in force

Travel times

How long the first wave took to reach each part of the ocean, one line for each hour up to 24, estimated from the source and the depth of the sea.

The travel times are computed in your browser, which needs JavaScript.

1 to 4 hours
5 to 6 hours
7 to 14 hours
15 hours and more

Computed in your browser the way NOAA’s own travel time maps are: the wave travels at the square root of gravity times the depth, over NOAA’s ETOPO1 depths averaged to a 10 arc-minute grid. Checked against NOAA NCEI’s maps for 21 tsunamis over the first 24 hours, these lines fall within 10 minutes of NCEI’s at half the points compared and within 52 minutes at 9 in 10. They give when the first wave could arrive, not how high it is; bays, harbors and island chains finer than the grid can see it later. Not for use in a warning: see tsunami.gov.

The tsunami

Date: September 9, 1780
Source: SW. Kyushu Island, Japan
Cause: Volcano
Volcano: The eruption that caused it
Maximum water height: 6 m (19.7 ft)
Runups recorded: 2
Tsunami intensity (Soloviev-Imamura): 1
Tsunami magnitude (Iida): 0
Waters: Ocean
How certain: Definite tsunami
Source location: 31.600° N, 130.700° E

The toll

Damage: Moderate (about $1 to $5 million)

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.

Eruption of Sakurajima Volcano.

Reference #414:

1780, September 9. A tsunami was observed on the coast of Kagoshima Bay (south of Kyushu Island). It was caused by an explosion of the Sakurajima volcano.

Reference #13929:

On Sept. 9th, 1780, at midnight, a submarine outburst took place, which sent up fires and smokes to a considerable hight, causing "tsunami," whose waves were 20 ft high at the beach of Koike on the W. coast of Sakura-jima, at the N.E. base of Hakamagoshi. The official report under the date of Nov. 28th, 1780, states that some of the new islets, which had arisen off the N.E. coast of Sakura-jima, gradually increased in size, and that the stronger submarine eruptions were accompanied by large seawater disturbances, which rushed in over tho neighbouring coasts and also flooded the strand streets of the Kagoshima city. The damage resulting from these "tsunami," up to Sept. 1780, was as follows :--permanent and temporary losses to cultivated fl.old, respectively 6 7 5 and 17,647 kolm ; numbers of houses completely and partially destroyed by the waves, respectively 168 and 630; habitation grounds washed by sea~water, 417 pieces; lengths of broken embankment roads, masonry walls, and river banks, respectively 11,380; 1,237; and 670 ken.* (1 ken = 6 feet nearly)

Reference #1686:

One of the latter eruptions, on 9 September 1780, generated waves up to 6 m in height […]

Every runup

Nearest the source first. Heights are above sea level at the time; a tide gauge reads half the wave’s full height.

Where	Country	Km from source	Water height, m	Inland, m	Measured by	First wave, UTC	Deaths
Koike, Sakurajima Is	Japan	10	6		Eyewitness observation of water height
Kagoshima Bay	Japan	13			Eyewitness observation of water height

Every tsunami in 1780 The 1700s Tsunamis of Japan The eruption This day in weather history Alerts in force

Sources

Tsunami events and runups from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-10-01. NCEI tsunami event 525.