M6.8 earthquake 39 km NW of Mýrina, Greece

Saturday, August 6, 1983, 15:43:51 UTC · 40.142°N, 24.766°E

A magnitude 6.8 earthquake struck 39 km NW of Mýrina, Greece on Saturday, August 6, 1983, 15:43:51 UTC, at a depth of 2.4 km (shallow). It is the strongest earthquake within 300 km since an M6.8 on January 18, 1982.

Magnitude: 6.8; Strong · mw
Depth: 2 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: VI; Strong (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

239 kilotons of TNT

That is about 16 times the Hiroshima bomb. It released about 501 times the energy of a magnitude 5.0.

Tectonic setting

7 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

2 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 99 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M4.7 on August 26, 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 270 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 88 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 28,571 recorded deaths. The most severe:

1883M7.3
Ayvalik, Izmir, Cesme
15 Oct 1883 · 239 km away · intensity X
15,000 deathsExtreme damage ($25M+)
1881M7.3
Khios; Turkey: Cesme
3 Apr 1881 · 246 km away · intensity XI
7,866 deathsExtreme damage ($25M+)tsunami
1912M7.2
Marmara Sea
9 Aug 1912 · 210 km away
2,800 deathsExtreme damage ($25M+)tsunami
1953M7.3
Yenice, Onon
18 Mar 1953 · 245 km away
1,070 deaths$4 million damage
1867M7.0
Mitilini; Turkey: Izmir
7 Mar 1867 · 175 km away
563 deathsSevere damage ($5–24M)tsunami
1894M6.7
Locride, Malesina-Martinon (Lokris)
20 Apr 1894 · 218 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