Reviewed by USGSGreece71y ago
M5.5 earthquake 22 km E of Amorgós, Greece
Monday, July 9, 1956, 20:13:57 UTC · 36.831°N, 26.156°E
A magnitude 5.5 earthquake struck 22 km E of Amorgós, Greece on Monday, July 9, 1956, 20:13:57 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.7 on July 9, 1956.
- Magnitude
- 5.5
- 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 earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
3 kilotons of TNT
That is about 1/6 of the Hiroshima bomb. It released about 6 times the energy of a magnitude 5.0.
Tectonic setting
193 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 lists 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.7 on July 10, 1956. 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 166 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.9Southern GreeceAugust 11, 1903 · 297 km W of this epicenter
- 7.719 km SSE of Amorgós, GreeceJuly 9, 1956 · 26 km SW of this epicenter
- 7.315 km NNW of Karpathos, GreeceFebruary 9, 1948 · 160 km SE of this epicenter
- 7.29 km NNW of Karaburun, TurkeyJuly 23, 1949 · 212 km N of this epicenter
- 7.03 km ESE of Soma, TurkeyNovember 18, 1919 · 292 km NE of this epicenter
- 7.05 km NNW of Kéfalos, GreeceJune 26, 1926 · 69 km E of this epicenter
- 6.7TurkeyOctober 6, 1944 · 300 km N of this epicenter
- 6.733 km SE of Karpathos, GreeceAugust 13, 1922 · 207 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 62 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 31,050 recorded deaths. The most severe:
- 1883M7.3
Ayvalik, Izmir, Cesme
15 Oct 1883 · 163 km away · intensity X
15,000 deathsExtreme damage ($25M+)
- 1881M7.3
Khios; Turkey: Cesme
3 Apr 1881 · 158 km away · intensity XI
7,866 deathsExtreme damage ($25M+)tsunami
- 1810
Crete: Iraklion (Candia)
16 Feb 1810 · 181 km away · intensity X
3,000 deathsSevere damage ($5–24M)tsunami
- 1750
Morea,Cerigo
7 Jun 1750 · 291 km away · intensity X
2,000 deaths
- 1899M6.7
Sultanhisar,Atca,Nazilli,Kuyucak,Denizli
20 Sep 1899 · 267 km away · intensity IX
1,117 deathsSevere damage ($5–24M)
- 1856
Crete; Egypt
12 Oct 1856 · 149 km away · intensity XI
600 deathsSevere damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.