The 7.8 Mw Erzincan earthquake shakes eastern Turkey with a maximum Mercalli intensity of XI (Extreme). At least 32,700 people were killed.

An earthquake struck Turkey's eastern Erzincan Province at 1:57:23 a.m. on 27 December 1939 local time with a moment magnitude (Mw) of 7.8 and maximum Mercalli intensity of XII (Extreme). It is tied with the 2023 Turkey–Syria earthquakes as the most powerful earthquake in Turkey to be recorded by instruments. However, it was less powerful than estimates of the 1668 North Anatolia earthquake. This was one of the largest in a sequence of violent shocks to affect Turkey along the North Anatolian Fault between 1939 and 1999. Surface rupturing, with a horizontal displacement of up to 3.7 meters, occurred in a 360 km long segment of the North Anatolian Fault Zone. The earthquake was the most severe natural loss of life in Turkey in the 20th century, with 32,968 dead, and some 100,000 injured.