July 17, 1793 Tsunami: Plymouth, England, United Kingdom
A tsunami of unknown cause began at Plymouth, England, United Kingdom on July 17, 1793.
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
- July 17, 1793
- Source
- Plymouth, England, United Kingdom
- Cause
- Unknown
- Runups recorded
- 0
- Waters
- Ocean
- How certain
- Very doubtful tsunami
- Source location
- 50.363° N, 4.142° 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.
Plymouth, July 17. This morning, between seven and eight o'clock, the tide flowed into the harbour in a very extraordinary and rapid manner; it rose two feet perpendicular in nine minutes, and as rapidly receded again, and this it did three times in the space of less than an hour; it ran so very swift into the Pool, that it was impossible for a rowing boat to make head against it; one vessel lost her bowsprit, by being run foul of by another that became perfectly unmanageable, owing to the rapidity of the current. Nothing of the kind has been observed here since the great Earthquake at Lisbon, when the tide flowed and ebbed nearly in the same extraordinary manner as this morning. (reference #7635)
More
Every tsunami in 1793The 1700sTsunamis of United KingdomThis 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 4962.