M5.5 earthquake southern Greece

Sunday, February 20, 1983, 12:42:31 UTC · 37.898°N, 21.080°E

A magnitude 5.5 earthquake struck southern Greece on Sunday, February 20, 1983, 12:42:31 UTC, at a depth of 36.8 km (shallow). It is the strongest earthquake within 300 km since an M5.6 on January 19, 1983.

Magnitude: 5.5; Moderate · ms
Depth: 37 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: V; Moderate (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

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

60 km

from the nearest mapped plate boundary, between the Aegean Sea and Eurasian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

37 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 8 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.2 on March 15, 1983. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 380 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 137 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5,518 recorded deaths. The most severe:

1750
Morea,Cerigo
7 Jun 1750 · 254 km away · intensity X
2,000 deaths
1953M7.2
Lixouri-Argostoli (Kephallenia)
12 Aug 1953 · 51 km away · intensity X
476 deaths$100 million damagetsunami
1820M6.9
Zakinthos (Zante)
29 Dec 1820 · 22 km away · intensity X
388 deathsSevere damage ($5–24M)tsunami
1886M6.8
Triphylie (Peleponese), Philiatra
27 Aug 1886 · 104 km away · intensity X
326 deathsSevere damage ($5–24M)tsunami
1767M6.7
Kefalonia
11 Jul 1767 · 68 km away · intensity X
303 deathsSevere damage ($5–24M)
1894M6.7
Locride, Malesina-Martinon (Lokris)
20 Apr 1894 · 201 km away · intensity X
255 deathsSevere damage ($5–24M)

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers