The 1972 Qir earthquake occurred at 05:36 local time (02:06 UTC) on April 10, 1972. It had a magnitude of 6.7 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...

and a maximum perceived intensity of IX (''Violent'') 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 epicentre was in the province of Fars in southern Iran. 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 ...

caused the destruction of

Qir Qir or Gheer ( fa, قير, also Romanized as Qīr) is a city in the Central District (Qir and Karzin County), Central District of Qir and Karzin County, Fars province, Fars province, Iran, serving as both capital of the district and of the county. ...

and serious damage to towns and villages in the surrounding area. The estimated number of deaths is 5,374, with a further 1,710 injured.

Tectonic setting

The earthquake occurred in the Fars Domain of the Zagros fold and thrust belt, which forms part of the collisional zone between the Arabian Plate 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 Fars Domain lies at the southeastern end of the Zagros and is part of the 'simply folded belt', which is characterised by detachment folding over the late Neoproterozoic to Early Cambrian Hormuz salt layer. Most earthquakes have epicenters beneath the salt layer and are thought to represent reverse faulting in the underlying

basement A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ...

, possibly involving the reactivation of older rift faults.

Earthquake

The earthquake is thought to have been caused by rupture along a WNW-ESE trending reverse fault. The

focal mechanism The focal mechanism of an earthquake describes the deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is ...

suggests that the reverse fault is moderately-dipping to either south or north. The earthquake was preceded by a series of

foreshock A foreshock is an earthquake that occurs before a larger seismic event (the mainshock) and is related to it in both time and space. The designation of an earthquake as ''foreshock'', ''mainshock'' or aftershock is only possible after the full sequ ...

s in March 1972, which caused some of the inhabitants of Hingam and Karzin to move out of their houses.

Damage

Initial casualty reports (compiled on April 28, 1972) showed that there were 3,399 deaths in Qir (two-thirds of the population), with a further 889 injured. There were 400 deaths in Gavakei (almost half of the population) and a further 300 in Bian (a third of the population) and 150 in Sekehravan (about a quarter of the population). The total number of deaths based on initial reports was 5,374 with a further 1,710 injured. The methods of construction used in that affected area led to the high levels of damage. Most buildings were built of

adobe Adobe ( ; ) is a building material made from earth and organic materials. is Spanish for ''mudbrick''. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of e ...

brick with a relatively heavy flat roof of thick

date palm ''Phoenix dactylifera'', commonly known as date or date palm, is a flowering plant species in the palm family, Arecaceae, cultivated for its edible sweet fruit called dates. The species is widely cultivated across northern Africa, the Middle Eas ...

beams resting directly on the brick walls. The addition of layers of mud and straw for waterproofing increased the load on the walls. These structures have a very low resistance to earthquake shaking and most of the deaths occurred due to the collapse of such buildings. More modern types of construction generally fared little better, as they were not properly engineered and lacked many of the elements that would have made them more resistant. Even some of the engineered buildings were badly damaged due to poor design and construction techniques, such as a lack of anchoring between the steel roof I-beams and the reinforced concrete tie-beams on which they rested. One structure, the Shahabad bridge that was well-engineered and constructed using modern techniques, was almost undamaged, compared to the adobe houses in a neighbouring village, all of which collapsed. The earthquake caused damage to qanats (water tunnels), with the destruction of 180 wells. The flow of some springs was disrupted.

References

External links

* {{Earthquakes in Iran 1972 earthquakes Earthquakes in Iran History of Fars Province 1972 in Iran

Tectonic setting

Earthquake

Damage

See also

References

External links