How Turkey’s Anatolian Fault System Causes Devastating Earthquakes

By Leanne Abraham, Henry Fountain and K.K. Rebecca LaiUpdated Feb. 9, 2023

The major earthquake and large aftershock in Turkey on Monday are two of more than 70 quakes of magnitude 6.5 or higher recorded in the region since 1900. Turkey’s two main fault zones — the East Anatolian and the North Anatolian — make it one of the most seismically active regions in the world.

Magnitudes of major earthquakes since 1900

Map showing the East Anatolian and North Anatolian fault zones in Turkey. Points are overlaid on the map showing the locations of major earthquakes in the region since 1900.

Eurasian

Plate

Bulgaria

North Anatolian

Fault

Istanbul

Ankara

Iran

Turkey

East Anatolian

Fault

Feb. 6

Gaziantep

Anatolian Plate

Greece

Arabian Plate

Syria

Iraq

Beirut

Earthquake

magnitude

Damascus

African Plate

200 miles

Eurasian Plate

North Anatolian

Fault

Istanbul

Ankara

Turkey

East Anatolian

Fault

Feb. 6

Anatolian Plate

Arabian Plate

Syria

Iraq

Earthquake

magnitude

Beirut

Damascus

Tel Aviv

200 miles

Sources: National Oceanic and Atmospheric Administration; United States Geological Survey Notes: Includes earthquakes since 1900 that are classified as significant earthquakes by the National Centers for Environmental Information based on a series of criteria including deaths, damage and magnitude.

The 7.8-magnitude earthquake at 4:17 a.m. local time, and the unusually large 7.5-magnitude aftershock nine hours later, both were in the East Anatolian Fault Zone. But there have been several extremely deadly quakes in the North Anatolian Fault Zones as well, including one in 1999 about 60 miles from Istanbul that killed about 17,000 people.

These fault zones are a result of movement of large portions of Earth’s crust, or tectonic plates, relative to each other. One zone includes the Anatolian Plate, which makes up most of Turkey. The East Anatolian zone encompasses the area where there is movement of the Anatolian Plate relative to the Arabian Plate, which is to the southeast of the Anatolian. The North Anatolian zone is where there is movement of the Anatolian Plate and the Eurasian Plate, which is to the north of the Anatolian.

The main quake on Monday was one of the most powerful earthquakes ever recorded in the area, matching the magnitude of an earthquake that killed more than 30,000 people in December 1939 in northeast Turkey.

Deaths in major earthquakes since 1900

Around Turkey and northern Syria. Circles are sized by the number of estimated deaths.

Chart showing year and the number of deaths in earthquakes.

Magnitude

1900

1920

1940

1960

1980

2000

2023

Turkey, 1939

Magnitude

7.7

Est. deaths

32,000+

Armenia, 1988

Magnitude

6.8

Est. deaths

25,000+

Turkey, 1999

Magnitude

7.6

Est. deaths

17,000+

Turkey and Syria, 2023

Magnitude

7.8

Est. deaths

20,000+

as of 1 p.m. E.T. on Feb. 9

Sources: National Oceanic and Atmospheric Administration; United States Geological Survey Notes: Major earthquakes are those classified as significant earthquakes by the National Centers for Environmental Information based on a series of criteria, including deaths, damage and magnitude. Death tolls are estimates and are approximately assigned to the related event.