December 5, 1923 Tsunami: North Aegean Sea, Greece
A tsunami caused by a magnitude 6.4 earthquake began at North Aegean Sea, Greece on December 5, 1923 at 20:56:49 UTC. Its effects were recorded at 1 place.
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
- December 5, 1923, 20:56:49 UTC
- Source
- North Aegean Sea, Greece
- Cause
- Earthquake
- Earthquake
- Magnitude 6.4, 10 km deep
- Runups recorded
- 1
- Waters
- Ocean
- How certain
- Questionable tsunami
- Source location
- 39.820° N, 23.594° E
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.
The 5 December 1923, M = 6.4 Chalkidiki earthquake caused tsunami that have affected the coastal Kassandra area. (reference #13873)
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 |
|---|---|---|---|---|---|---|---|
| Kassandra, Halkidiki | Greece | 21 | Eyewitness observation of water height |
More
Every tsunami in 1923The 1900sTsunamis of GreeceThe 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 5946.