August 31, 1926 Tsunami: Azores, Portugal
A tsunami caused by a magnitude 5.8 earthquake began at Azores, Portugal on August 31, 1926 at 10:40:09 UTC. The water rose as high as 0.3 meters. Its effects were recorded at 1 place. It killed 9 people, counting the earthquake or eruption that caused it.
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, 1926, 10:40:09 UTC
- Source
- Azores, Portugal
- Cause
- Earthquake
- Earthquake
- Magnitude 5.8, 10 km deep
- Maximum water height
- 0.3 m (1.0 ft)
- Runups recorded
- 1
- Waters
- Ocean
- How certain
- Very doubtful tsunami
- Source location
- 37.973° N, 28.590° W
The toll
- Deaths
- 9 with the earthquake or eruption that caused it
- Injuries
- 200 with the earthquake or eruption that caused it
- Damage
- Moderate (about $1 to $5 million) with the earthquake or eruption that caused it
- Houses destroyed
- Many (101 to 1,000) with the earthquake or eruption that caused it
- Houses damaged
- Few (about 1 to 50) with the earthquake or eruption that caused it
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.
1926, August 31. 38.5 N 28.4 W. Concerning the event in 1926, Agostinho (1927) described a "... damaging earthquake on Fayal and Pico islands .... The people aboard the ships in the harbor [Horta--Faial Island] felt violently the earthquake, but only small waves nearly two feet high were formed which vanished in a few minutes. No tsunami was remarked in any other of the islands". This account suggests that the violence of the seismic shock had no direct correspondence in tsunami development. (reference #5046)
[Near Faial] The people aboard the ships in the harbour felt violently the earthquake, but only small waves nearly two feet high were formed which vanished in a few minutes. No tsunami was remarked in any other of the islands. (reference #12492)
1926, August 22. Azores. Epicenter approximately 38 deg 32'N., 28 deg 35'W. Damaging earthquake on Ilha de Fayal and Ilha do Pico. The people aboard the ships in the harbor (Horta) felt the earthquake violently, but only small waves nearly two feet high were formed. These waves vanished in a few minutes. No tsunami was noted in any of the other islands. (reference #41)
1926, August 31. Tsunami is listed as erroneous entry by reference #13057. [...] Miranda (1930) also indicates that the effects felt on board ships correspond to the seismic waves hitting them. The sea oscillations observed are not clear and may result from a vibration effect on Horta’s port and/or from the anchored ships themselves. (reference #13057)
Note: Reference #41 lists 22 August as the date
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 |
|---|---|---|---|---|---|---|---|
| Ilha DE Fayal, Azores | Azores | 67 | 0.3 | Eyewitness observation of water height |
More
Every tsunami in 1926The 1900sTsunamis of PortugalThe earthquakeThis 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 1570.