August 31, 1931 Tsunami: Azores, Portugal
A tsunami of unknown cause began at Azores, Portugal on August 31, 1931. 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
The tsunami
- Date
- August 31, 1931
- Source
- Azores, Portugal
- Cause
- Unknown
- Runups recorded
- 2
- Waters
- Ocean
- How certain
- Very doubtful tsunami
- Source location
- 38.400° N, 27.100° W
The toll
- Damage
- Limited (under about $1 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.
1931 August 31, Horta and Feteira, Ilha de Fayal, were damaged by a tidal wave. (reference #41 and #132)
1931 August 31, Seismic source tsunami (?), 38.4 N 27.1 W (?). (reference #5046)
1931 August 31, Very doubtful tsunami, Unknown cause. [...]there are no records of an earthquake that might have triggered a tsunami on this date. Moreover, the location presented by these authors is not compatible with the only existing description, since Terceira, S. Jorge and Pico islands would be affected first. (reference #13057)
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 |
|---|---|---|---|---|---|---|---|
| Horta, Ilha DE Fayal, Azores | Azores | 134 | |||||
| Feteira, Ilha DE Fayal, Azores | Azores | 139 |
More
Every tsunami in 1931The 1900sTsunamis of PortugalThis 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 1643.