May 8, 1939 Tsunami: Azores, Portugal
A tsunami caused by a magnitude 6.7 earthquake began at Azores, Portugal on May 8, 1939 at 01:46:53 UTC. The water rose as high as 0.2 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
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
- May 8, 1939, 01:46:53 UTC
- Source
- Azores, Portugal
- Cause
- Earthquake
- Earthquake
- Magnitude 6.7, 16 km deep
- Maximum water height
- 0.2 m (0.7 ft)
- Runups recorded
- 2
- Tsunami intensity (Soloviev-Imamura)
- 1
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 37.198° N, 24.356° W
The toll
- Damage
- Moderate (about $1 to $5 million) 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.
On 8 May 1939, a small-intensity tsunami was reported in newspapers (Correio dos Acores, 1939) that quote information supplied by the Meteorological Survey of Acores. Following an earthquake felt at 1:47 AM, three tsunami waves with amplitudes of circa 0.2 m were recorded by the tide gauge of Angra (Terceira) at 02:25 AM, 02:29 AM and 02:45 AM. The same tide gauge registered a tsunami of unreported amplitude on 25 November 1941... Apparently neither tsunami caused any damage in the Azores. (reference #5046)
A small tsunami was recorded at the tide stations of Ponta Delgada (S. Miguel) and Angra (Terceira Island). (reference #4649)
[...] the tsunami did not reach the Portuguese mainland coast. The low wave amplitudes and the fact that the tsunami occurred at night time may justify the absence of observations by the local inhabitants. (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 |
|---|---|---|---|---|---|---|---|
| Ponta Delgada | Azores | 131 | 0.08 | Tide gauge (half the maximum wave height) | day 8, 02:05 | ||
| Angra do Heroismo, Terceira | Azores | 301 | 0.2 | Tide gauge (half the maximum wave height) |
More
Every tsunami in 1939The 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 4258.