M6.4 earthquake 8 km ESE of Kolchikón, Greece

Tuesday, June 20, 1978, 20:03:21 UTC · 40.739°N, 23.229°E

A magnitude 6.4 earthquake struck 8 km ESE of Kolchikón, Greece on Tuesday, June 20, 1978, 20:03:21 UTC, at a depth of 3.0 km (shallow). It is the strongest earthquake within 300 km since an M6.7 on March 27, 1975.

Magnitude: 6.4; Strong · ms
Depth: 3 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: IX; Violent (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

60 kilotons of TNT

That is about 4 times the Hiroshima bomb. It released about 126 times the energy of a magnitude 5.0.

Tectonic setting

111 km

from the nearest mapped plate boundary, between the Aegean Sea and Eurasian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

3 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 100 km

USGS lists 50 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.1 on July 4, 1978. 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 287 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 94 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5,124 recorded deaths. The most severe:

1851M6.6
Vlore (Valona),Berat; Turkey
12 Oct 1851 · 299 km away · intensity XI
2,000 deathsExtreme damage ($25M+)tsunami
1963M6.0
Macedonia: Skopje
26 Jul 1963 · 221 km away · intensity X
1,070 deaths$1.0 billion damage
1851
Berat
17 Oct 1851 · 299 km away · intensity X
400 deathsSevere damage ($5–24M)
1894M6.7
Locride, Malesina-Martinon (Lokris)
20 Apr 1894 · 238 km away · intensity X
255 deathsSevere damage ($5–24M)
1920M6.2
Tepelene, Dragoti, Peshtani, Maricaj
26 Nov 1920 · 280 km away · intensity XI
200 deathsSevere damage ($5–24M)
1932M6.9
Hierissos-Strantonion (Chalkidiki)
26 Sep 1932 · 63 km away · intensity X
161 deathsExtreme damage ($25M+)tsunami

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

Nearby trackers