1976 Caldiran earthquake surface rupture

The 1976 Çaldıran–Muradiye earthquake occurred at 14:22 local time (12:22 UTC) 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. Surface damage Before the instrumental pe ...

was located near Çaldıran, 20 km northeast of

Muradiye Muradiye ( ku, Bêgirî, hy, Բերկրի, translit=Berkri) is a town and district in the Van Province of Turkey. History The tenth-century Byzantine text ''De Administrando Imperio'' mentions "Perkri" belonging to King Ashot I Bagratuni at th ...

, in the

Van Province Van Province ( tr, Van ili, ku, Parezgêha Wanê, Armenian: Վանի մարզ) is a province in the Eastern Anatolian region of Turkey, between Lake Van and the Iranian border. It is 19,069 km2 in area and had a population of 1,035,418 at ...

of eastern

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

. The

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...

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, ma ...

of X (''Extreme'') on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the eff ...

. 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 boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains prod ...

between the

Arabian Plate The Arabian Plate is a minor tectonic plate in the Northern and Eastern Hemispheres. It is one of the three continental plates (along with the African and the Indian Plates) that have been moving northward in geological history and collidin ...

and the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

. 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 Caldiran Earthquakes in Iran 1976 earthquakes 1976 in Turkey

1976 Events January * January 3 – 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 11 – The 1976 Phila ...

November 1976 events in Asia 1976 disasters in Turkey

Tectonic setting

Earthquake

Damage

See also

References

External links