1983 Hindu Kush earthquake

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Coordinates: 36°22′19″N 70°44′17″E / 36.372°N 70.738°E / 36.372; 70.738
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1983 Hindu Kush earthquake
1983 Hindu Kush earthquake is located in Afghanistan
1983 Hindu Kush earthquake
1983 Hindu Kush earthquake is located in Pakistan
1983 Hindu Kush earthquake
UTC time1983-12-30 23:52:39
ISC event563957
USGS-ANSSComCat
Local dateDecember 31, 1983 (1983-12-31)
Local time03:52:39 PST
MagnitudeMw  7.4[1]
Depth214.5 km
Epicenter36°22′19″N 70°44′17″E / 36.372°N 70.738°E / 36.372; 70.738
Max. intensityMMI VII (Very strong)
MSK-64 VII (Very strong)[2]
Casualties26 dead, 483 + "hundreds" injured[3]

The 1983 Hindu Kush earthquake occurred south of

moment magnitude 7.4 quake affected three countries,[1] killing at least 26 people and injuring several hundred.[3]

Tectonic setting

The Afghanistan-Pakistan-Tajikistan border region lies within the broad zone of ongoing crustal deformation caused by

reverse fault focal mechanisms, which for the near-vertical slab indicates active extension. It has been proposed that these earthquakes are a result of "necking" of the downgoing slab, a process that may eventually lead to break-off.[4]

Smaller shallow focus earthquakes are also observed in the region, particularly associated with north–south trending zones of right lateral strike-slip, such as the Chaman Fault, with an increasing degree of shortening to the north, together accommodating the highly oblique convergence between the Indian plate and the Eurasian plate.[5]

Earthquake

The most recent large event of this type was the

U.S. Geological Survey indicated intermediate-depth reverse faulting.[1] The seismogenic fault beneath the Hindu Kush is thought to have produced four magnitude 7.3–7.5 earthquakes between 1949 and 2015, and two 7.0 events in 1974 and 1993. The magnitude 7.3–7.5 earthquakes had an estimated 1.2 meters, and 0.7 meters for the 7.0 earthquakes, resulting in a total displacement of 6.2 meters along the same fault through 1949 and 2015, distributed across six earthquakes. Vertical necking or stretching of the rapidly moving (10 cm/yr) downgoing slab in the vicinity of the source fault encourages a high slip rate of 9.6 cm/year. The estimated slip rate is much faster than the 1 cm/yr convergent rate at the surface.[7]

Waveform inversion using the Bayesian information criterion revealed the earthquake consisted of two subevents with the latter about 20 km away from the first subevent. The first event occurred near the hypocenter along the fault. It's estimated that the latter subevent released seven times the seismic moment of the former.[8]

Other events

Two years after the 1983 quake, the Hindu Kush region was hit with another magnitude 7.4 quake. It struck with an epicenter 30 km southwest of the 1983 event at 98.7 km beneath the mountains. Five people died and 38 were injured in the

Qurgonteppa, USSR. The earthquake was also felt strongly at New Delhi, India.[9]

Impact

A total of 26 people died; 12 in Kabul and Samangan, Afghanistan, and 14 at Peshawar, Pakistan. Many died or were injured when their homes collapsed during their sleep. Several hundred people were injured in Pakistan and 483 were reported in Afghanistan. Eight members of one family were injured in Lahore.[10] Damage was also reported in the USSR, now Tajikistan.[3]

See also

References

  1. ^ a b c "M 7.4 – 55 km S of Jurm, Afghanistan". United States Geological Survey. Retrieved 13 October 2021.
  2. ^ International Seismological Centre. Event Bibliography. Thatcham, United Kingdom. [Event 563957].
  3. ^ a b c "Significant Earthquake Information". National Geophysical Data Center. Retrieved 13 October 2021.
  4. S2CID 31948667
    .
  5. S2CID 130945532
    .
  6. ^ "M 7.5 – Hindu Kush region, Afghanistan". United States Geological Survey. 26 October 2015. Retrieved 13 October 2021.
  7. S2CID 31948667
    . Retrieved 13 October 2021.
  8. doi:10.1016/0031-9201(89)90172-6
    .
  9. ^ "M 7.4 – 75 km S of Jurm, Afghanistan". United States Geological Survey. Retrieved 13 October 2021.
  10. ^ "Pakistan quake kills 12". Vol. 127, no. 61. Press Democrat. Associated Press. 1 January 1984. p. 13. Retrieved 15 May 2023.
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