November 2, 1755 Tsunami: SW Portugal
A tsunami caused by an earthquake began at SW Portugal on November 2, 1755.
Where the waves reached
The source of the tsunami. No runup with a place is recorded for it.
- 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
- November 2, 1755
- Source
- SW Portugal
- Cause
- Earthquake
- Runups recorded
- 0
- Waters
- Ocean
- How certain
- Very doubtful tsunami
- Source location
- 37.000° N, 10.000° 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.
Large ebb and flood in Gibraltar. Very Improbable tsunami. (reference #4149)
The 2 November 1755 event is one among a large sequence of aftershocks of the 1755 earthquake, which stood until March 1756. On 2 November the day after the earthquake, a shock was felt and the sea was described as agitated (Rodriguez, 1932). All coeval sources report extensively the aftershocks but the exact date of this event is rather uncertain (Rodriguez, 1932). The epicentre coordinates are considered to be 37.00 N and −10.50 E by the Martins and Victor (2001) catalog but the magnitude if this event is listed as Mb=3, incompatible with the generation of a tsunami. According to the on-line version of the Spanish Tsunami Catalog (Instituto Geografico Nacional, 2005) water flux and reflux was also described in Gibraltar but a tsunami reliability of zero is attributed. Mendonca (1758) reports aftershocks during the following day, “in the 24 hours after the earthquake the earth continued shaking” but no tsunami is reported. (reference #4649)
More
Every tsunami in 1755The 1700sTsunamis 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 4267.