1976 Caldiran earthquake surface rupture

The 1976 Çaldıran–Muradiye earthquake occurred at 14:22 local time (12:22

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

) on 24 November. The

epicenter The epicenter (), epicentre, or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Determination The primary purpose of a ...

was located near Çaldıran, 20 km northeast of

Muradiye Muradiye (, ) is a municipality and district of Van Province, Turkey. Its area is 912 km2, and its population is 45,718 (2022). It is best known for its impressive waterfalls. History The tenth-century Byzantine text ''De Administrando Impe ...

, in the

Van Province Van Province (, , Armenian: Վանի մարզ) is a province and metropolitan municipality in the Eastern Anatolian region of Turkey, between Lake Van and the Iranian border. Its area is 20,921 km2, and its population is 1,128,749 (2022). ...

of eastern

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

. The

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

had a

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of 7.3 with a maximum

intensity Intensity may refer to: In colloquial use * Strength (disambiguation) *Amplitude * Level (disambiguation) * Magnitude (disambiguation) In physical sciences Physics *Intensity (physics), power per unit area (W/m2) *Field strength of electric, m ...

of X (''Extreme'') on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS) measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake. Magnitude scales measure the inherent force or ...

. The area of severe damage, where over 80% of the buildings were destroyed, covered an area of 2,000 square kilometres. There were between 4,000 and 5,000 casualties.

Tectonic setting

The easternmost part of Turkey lies within the complex zone of continuing

continental collision In geology, continental collision is a phenomenon of plate tectonics that occurs at Convergent boundary, convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroy ...

between the Arabian plate and the Eurasian plate. The overall shortening that affects this area is accommodated partly by thrusting along the Bitlis-Zagros fold and thrust belt and partly by a mixture of sinistral strike-slip on SW-NE trending faults and dextral strike-slip on NW-SE trending faults. The earthquake was caused by movement on the Çaldıran Fault, one of the dextral faults, which had not been recognized before the earthquake. No earthquakes with magnitudes of 6 or greater were recorded within 100 km of Çaldıran in the preceding 74 years, possibly explaining why it was considered an area of only intermediate seismic risk (zone 3 out of the five-zone system of seismic risking used in Turkey at the time, with zone 1 being the highest).

Earthquake

The earthquake was associated with a 50–55 km zone of surface faulting, extending from three kilometres west of Sarikök in the west to just west of Baydoğan in the east. A maximum dextral offset of 3.5 m was recorded. The rupture width was estimated at 24 km and the fault zone was found to dip at 78° to the south. The duration of strong ground shaking is estimated at six seconds.

Damage

In Çaldıran, 95% of the houses were destroyed with all the others damaged to some extent, and 615 of the 3,304 inhabitants were killed. In the villages around Çaldıran, over 80% of the houses were destroyed and most of the rest were damaged; 2,313 of the 27,587 inhabitants were killed. In Muradiye, almost all the houses were either completely collapsed or damaged, and 159 of the 6,753 inhabitants were killed. Most of the buildings in the epicentral area were constructed of thick walls made from rubble masonry cemented with mud mortar. The structures were typically finished with a heavy earth roof with wooden supports. The very low resistance to lateral loads of these structures explains why almost all the buildings in Çaldıran collapsed in the earthquake, causing most of the deaths. Reinforced concrete structures generally performed well, with none suffering complete collapse. The performance of brick or stone masonry structures was mixed, with some collapsing and others being apparently unaffected.

References

External links

* {{DEFAULTSORT:Caldiran Muradiye 1976 1976 disasters in Turkey 1976 earthquakes 1976 in Turkey Earthquakes in Iran 1976 Caldiran

1976 Events January * January 2 – The International Covenant on Economic, Social and Cultural Rights enters into force. * January 5 – The Pol Pot regime proclaims a new constitution for Democratic Kampuchea. * January 18 – Full diplomatic ...

November 1976 in Turkey Strike-slip earthquakes

Tectonic setting

Earthquake

Damage

See also

References

External links