September 12, 1866 Tsunami: Manua Islands, American Samoa, US Territories
A tsunami caused by a volcano began at Manua Islands, American Samoa, US Territories on September 12, 1866. Its effects were recorded at 1 place.
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
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 12, 1866
- Source
- Manua Islands, American Samoa, US Territories
- Cause
- Volcano
- Volcano
- The eruption that caused it
- Runups recorded
- 1
- Waters
- Ocean
- How certain
- Very doubtful tsunami
- Source location
- 14.214° S, 169.590° W
The toll
The record gives no deaths, injuries or damage for this tsunami.
What the record says
NCEI’s account, from the sources it cites.
An underwater volcanic eruption that caused a disturbance of the sea originated about 3 km from the island of Olosega and 9 km from Tau, in the vicinity of the Manua Islands. The destruction continued all that day and through part of the next. A column of thick smoke rose to a height of 600 m. The seas heaved violently, and high waves around the center of the eruption continued for 3 days. The sea was extremely disturbed. Explosions continued for at least two months. (reference #415)
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 |
|---|---|---|---|---|---|---|---|
| Manu'A Islands, American Samoa, AS | US Territories | 8 | Eyewitness observation of water height |
More
Every tsunami in 1866The 1800sTsunamis of US TerritoriesThe eruptionThis day in weather historyAlerts 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 2026-09-24. NCEI tsunami event 958.