March 20, 1731 Tsunami: Tyrrhenian Sea, Italy
A tsunami caused by a magnitude 6.3 earthquake began at Tyrrhenian Sea, Italy on March 20, 1731 at 02:30 UTC. Its effects were recorded at 3 places. It killed 3,600 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
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
- March 20, 1731, 02:30 UTC
- Source
- Tyrrhenian Sea, Italy
- Cause
- Earthquake
- Earthquake
- Magnitude 6.3
- Runups recorded
- 3
- Tsunami intensity (Soloviev-Imamura)
- 4
- Waters
- Ocean
- How certain
- Probable tsunami
- Source location
- 41.500° N, 15.500° E
The toll
- Deaths
- 3,600 with the earthquake or eruption that caused it
- Damage
- Severe (about $5 to $25 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.
An extremely strong earthquake took place in the region of Apulia and in Naples. The first strongest shocks in Foggia reduced to ruins most of both public and private houses; about 500 people were killed. About 50 strong shocks occurred till April 17; the water splashed out of the wells. Strong shocks were noted in Barletta, Cerignola, Canosa (di Puglia), Melfi, S. Severo, Andria, Bari; altogether about 3,600 people were killed (reference #2130).
1731 Mar 20, 41.27 N 15.75 E. Definite tsunami. On 20 March 1731, one of the strongest earthquakes (IX MCS) ever occurred in the area of Foggia (CPTI 2004). The epicentre was located inland, near Foggia, about 30 km from the coast. According to Cirillo (1731), tsunami effects were observed at Siponto and Barletta, where a sudden sea rise nearly caused shipwrecking of some boats. Cirillo mentions this phenomenon to have occurred on 9 March rather than on 20 March, which should be taken as a material mistake in the quotation of the date. The probable tsunami is mentioned by Mallet (1853) [ref #521], reporting the same description as found in Cirillo’s paper (Fig. 5).(reference #9531)
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 |
|---|---|---|---|---|---|---|---|
| Siponto | Italy | Eyewitness observation of water height | |||||
| Barletta | Italy | Eyewitness observation of water height | |||||
| Apulia | Italy | Eyewitness observation of water height |
More
Every tsunami in 1731The 1700sTsunamis of ItalyThe 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 3159.