Magnitude7.8

Reviewed by USGSTurkey88y ago

M7.8 earthquake 20 km NNE of Erzincan, Turkey

Tuesday, December 26, 1939, 23:57:23 UTC · 39.907°N, 39.586°E

A magnitude 7.8 earthquake struck 20 km NNE of Erzincan, Turkey on Tuesday, December 26, 1939, 23:57:23 UTC, at a depth of 20.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.

Magnitude
7.8
Major · mw
Depth
20 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
VIII
Severe (ShakeMap)
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

7.6 megatons of TNT

That is about 502 times the Hiroshima bomb. It released about 15,849 times the energy of a magnitude 5.0.

Tectonic setting

11 km

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

Depth: shallow

20 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 200 km

USGS lists 3 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.6 on December 27, 1939. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M7M81h6h1d3d7d14d30dMainshock M7.8
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 5.513 km ESE of Mesudiye, Turkey87y ago · 152 km W of this epicenter
  2. 5.6Turkey88y ago · 36 km W of this epicenter
  3. 5.69 km E of Aksu, Turkey88y ago · 124 km W of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 24 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 23 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 57,984 recorded deaths. The most severe:

  1. 1939M7.8

    Erzincan

    26 Dec 1939 · 0 km away · intensity XII

    32,700 deaths$20 million damagetsunami

  2. 1859M6.1

    Erzurum

    2 Jun 1859 · 146 km away

    15,000 deathsSevere damage ($5–24M)

  3. 1784

    Erzurum,Erzincan

    23 Jul 1784 · 24 km away

    5,000 deathsSevere damage ($5–24M)

  4. 1903M6.3

    Malazgirt

    28 Apr 1903 · 266 km away · intensity X

    3,560 deathsExtreme damage ($25M+)

  5. 1903M5.8

    Varginis,Cardahli,Mehkerek

    28 May 1903 · 286 km away · intensity VIII

    1,000 deathsSevere damage ($5–24M)

  6. 1893M6.7

    Malatya

    31 Mar 1893 · 210 km away · intensity IX

    400 deathsSevere damage ($5–24M)

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

Nearby trackers

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