373 BC Earthquake: Greece
A magnitude 7.3 earthquake struck Greece in 373 BC. It caused a tsunami.
Map
Where it struck, with the other significant earthquakes within 200 km. Circles are sized and colored by magnitude; select one for its page.
The earthquake
- Date
- 373 BC
- Place
- Greece
- Magnitude
- 7.3 (Ms)
- Intensity
- 11 on the Modified Mercalli scale
- Tsunami
- Yes: the tsunami it caused
- Epicenter
- 38.250° N, 22.250° E
- Country
- Greece
The toll
- Deaths
- Many (about 101 to 1,000)
- Damage
- Severe (about $5 to $25 million)
- Houses destroyed
- Many (101 to 1,000)
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.
373 B.C., winter, night. Ionian Sea, Gulf of Corinth. A strong underground shock destroyed Boura and Helike, situated on the southern coast of the gulf. Helike was completely flooded with water and all its inhabitants were killed. (reference #2130)
373 B.C. Allegedly a major earthquake in the Gulf of Corinth. It happened in the winter when Asteus was archon at Athens [3] (373–372 BC). Only two towns in Achaea are said to have borne the brunt of the earthquake, Helice and Bura [4][...] There is no evidence that the earthquake caused any serious damage elsewhere, and nearby towns, as important as Helice, are not mentioned in the sources as having suffered from the earthquake. The effects of the shock did not extend beyond the region of Aegium [9] [...] The Helice earthquake must be classed as one of those which excited widespread interest and sympathy on account of the nature of the locality and religious implications rather than because of its large size. The effects of the earthquake of 373 BC are invariably exaggerated by modern writers and consequently the magnitude of the event is over-estimated at 7.0 (Marinatos 1960; Papazachos and Papazachou 1989, 223). (reference #9116)
no genuine, reliable information about the loss of Helike is offered by ancient Greek authors cited by authors of the Roman period. (reference #13056)
Other significant earthquakes nearby
Within 200 km, the deadliest first.
- December 856, Korinthos,patrai (Patras), Greece
- July 7, 551, Schisma, Boetia, Greece
- June 426 BC, Euboea, Greece
- September 30, 1636, Cephalonia, Greece
- August 12, 1953, Lixouri-Argostoli (Kephallenia), Greece
- December 29, 1820, Zakinthos (Zante), Greece
- August 27, 1886, Triphylie (Peleponese), Philiatra, Greece
- July 11, 1767, Kefalonia, Greece
- April 20, 1894, Locride, Malesina-Martinon (Lokris), Greece
- February 4, 1867, Cephalonia, Greece
- September 7, 1999, Athens, Greece
- August 23, 1817, Aeghion, Achaia, Greece
- February 25, 1742, Zakynthos, Greece
- August 1, 1870, Itea Delphi (Phokis), Greece
- September 30, 1870, Greece
More
Significant earthquakes of 373 BCThe 300s BCRecent earthquakes near here
Sources
Significant earthquakes 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 earthquake 20.