Reviewed by USGSGreece59y ago
M5.6 earthquake 53 km NW of Eresós, Greece
Tuesday, February 20, 1968, 02:21:53 UTC · 39.460°N, 25.433°E
A magnitude 5.6 earthquake struck 53 km NW of Eresós, Greece on Tuesday, February 20, 1968, 02:21:53 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on February 19, 1968.
- Magnitude
- 5.6
- Moderate · mw
- Depth
- 10 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
4 kilotons of TNT
That is about 1/4 of the Hiroshima bomb. It released about 9 times the energy of a magnitude 5.0.
Tectonic setting
46 km
from the nearest mapped plate boundary, between the Aegean Sea and Anatolian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
10 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 75 km
USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.3 on February 20, 1968. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 204 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.37 km N of Gönen, TurkeyMarch 18, 1953 · 205 km NE of this epicenter
- 7.2Aegean SeaNovember 8, 1905 · 98 km NW of this epicenter
- 7.225 km SE of Malkara, TurkeyAugust 9, 1912 · 201 km NE of this epicenter
- 7.29 km NNW of Karaburun, TurkeyJuly 23, 1949 · 122 km SE of this epicenter
- 7.03 km ESE of Soma, TurkeyNovember 18, 1919 · 193 km E of this epicenter
- 7.055 km S of Mýrina, GreeceFebruary 19, 1968 · 41 km W of this epicenter
- 6.97 km NNE of Ágios Nikólaos, GreeceSeptember 26, 1932 · 173 km NW of this epicenter
- 6.86 km SW of Galaxídhion, GreeceMarch 31, 1965 · 296 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 82 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 28,576 recorded deaths. The most severe:
- 1883M7.3
Ayvalik, Izmir, Cesme
15 Oct 1883 · 145 km away · intensity X
15,000 deathsExtreme damage ($25M+)
- 1881M7.3
Khios; Turkey: Cesme
3 Apr 1881 · 152 km away · intensity XI
7,866 deathsExtreme damage ($25M+)tsunami
- 1912M7.2
Marmara Sea
9 Aug 1912 · 201 km away
2,800 deathsExtreme damage ($25M+)tsunami
- 1953M7.3
Yenice, Onon
18 Mar 1953 · 205 km away
1,070 deaths$4 million damage
- 1867M7.0
Mitilini; Turkey: Izmir
7 Mar 1867 · 88 km away
563 deathsSevere damage ($5–24M)tsunami
- 1894M6.7
Locride, Malesina-Martinon (Lokris)
20 Apr 1894 · 215 km away · intensity X
255 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.