Reviewed by USGSGreece71y ago
M5.4 earthquake 15 km ENE of Astypálaia, Greece
Sunday, July 22, 1956, 03:29:00 UTC · 36.617°N, 26.497°E
A magnitude 5.4 earthquake struck 15 km ENE of Astypálaia, Greece on Sunday, July 22, 1956, 03:29:00 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M5.7 on July 10, 1956.
- Magnitude
- 5.4
- Moderate · mw
- Depth
- 15 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 earthquake
In context
How big was it, and why here?
Energy released
2 kilotons of TNT
That is about 1/9 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.
Tectonic setting
172 km
from the nearest mapped plate boundary, between the Aegean Sea and Anatolian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
15 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 has not published any M2.5+ earthquake within 75 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 161 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.719 km SSE of Amorgós, GreeceJuly 9, 1956 · 48 km W of this epicenter
- 7.315 km NNW of Karpathos, GreeceFebruary 9, 1948 · 124 km SE of this epicenter
- 7.29 km NNW of Karaburun, TurkeyJuly 23, 1949 · 234 km N of this epicenter
- 7.05 km NNW of Kéfalos, GreeceJune 26, 1926 · 44 km NE of this epicenter
- 6.815 km SSW of Kaş, TurkeyMarch 18, 1926 · 284 km E of this epicenter
- 6.733 km SE of Karpathos, GreeceAugust 13, 1922 · 170 km SE of this epicenter
- 6.6TurkeyJuly 16, 1955 · 131 km NE of this epicenter
- 6.59 km NNW of Bergama, TurkeySeptember 22, 1939 · 293 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 49 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 29,001 recorded deaths. The most severe:
- 1883M7.3
Ayvalik, Izmir, Cesme
15 Oct 1883 · 189 km away · intensity X
15,000 deathsExtreme damage ($25M+)
- 1881M7.3
Khios; Turkey: Cesme
3 Apr 1881 · 183 km away · intensity XI
7,866 deathsExtreme damage ($25M+)tsunami
- 1810
Crete: Iraklion (Candia)
16 Feb 1810 · 183 km away · intensity X
3,000 deathsSevere damage ($5–24M)tsunami
- 1899M6.7
Sultanhisar,Atca,Nazilli,Kuyucak,Denizli
20 Sep 1899 · 254 km away · intensity IX
1,117 deathsSevere damage ($5–24M)
- 1856
Crete; Egypt
12 Oct 1856 · 132 km away · intensity XI
600 deathsSevere damage ($5–24M)tsunami
- 1867M7.0
Mitilini; Turkey: Izmir
7 Mar 1867 · 287 km away
563 deathsSevere damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.