August 12, 1953 Tsunami: Ionian Sea, Greece

Name: August 12, 1953 Tsunami: Ionian Sea, Greece
Start: 1953-08-12
Location: Ionian Sea, Greece

August 12, 1953 · 476 deaths · $100 million · 30,439 houses destroyed · Probable tsunami

A tsunami caused by a magnitude 7.2 earthquake began at Ionian Sea, Greece on August 12, 1953 at 09:23:52 UTC. Its effects were recorded at 3 places. It killed 476 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

Tsunami warnings in force

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: August 12, 1953, 09:23:52 UTC
Source: Ionian Sea, Greece
Cause: Earthquake
Earthquake: Magnitude 7.2
Runups recorded: 3
Waters: Ocean
How certain: Probable tsunami
Source location: 38.300° N, 20.800° E

The toll

Deaths: 476 with the earthquake or eruption that caused it
Injuries: 2,412 with the earthquake or eruption that caused it
Damage: $100 million with the earthquake or eruption that caused it
Houses destroyed: 30,439 with the earthquake or eruption that caused it
Houses damaged: 2,394 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.

From August 9 - 12, 1953, three destructive earthquakes occurred on the Islands of Kefallonia, Ithaca, Zakynthos growing in force with intensity: Intensity = VIII - at 09"40m [local time] on August 9, Intensity = IX - at 17h32m [local time] on August 11, Intensity = X - at llh24m [local time] on August 12.

According to assertions of M. Grandazzi, who had been in the tourist camp near Argostoli on the Island of Kefallonia during the earthquake, no tsunami waves accompanied the earthquakes in spite of publicity in the press. Seaquakes took place. Sea level remained unchanged, and that the water did not flood the beach. The chief Greek seismologist professor A Galanopoulos confirmed in a later letter to an eyewitness that there had been no tsunami waves on the Ionian Islands. In spite of this, it was said in publications [Kolosenko, 1955; Ambraseys, 1965a], based on press reports, that part of the Zslund of Zthacu had slid into the sea, and that the generated sea wave had flooded the port of Vathi.

(above from reference #2130)

Reference #2427 assigns validity 3 and intensity 2 to the tsunami.

According to the eyewitnesses, the sea was boiling in several parts of Argostoli Bay, whirlpools were also observed, while repeated cycles of coastal inundation and sea withdrawal affected several parts of the bay (TAXYDROMOS, 14.08.1953). The waves inundated the coastal area and reached the Argostoli square (ELEFTHERIA, 13.08.1953). Many boats near the waterfront immediately raised their anchors so as not to be damaged by the waves that were triggered by the earthquake (TA NEA, 13.08.1953). This disturbance of the sea was also mentioned by Petratos. Based on information by prisoners in Argostoli prison, a tsunami has flooded the coast of Argostoli Bay (reference #13476)

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	Inland, m	Measured by
Vathi, Ithaki	Greece	10		Eyewitness observation of water height
Poros, Cephalonia Isl	Greece	17		Eyewitness observation of water height
Argostoli	Greece	31	100	Eyewitness observation of water height

Every tsunami in 1953 The 1900s Tsunamis of Greece The earthquake This day in weather history Alerts 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 3398.