1981 Golbaf earthquake

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1981 Golbaf earthquake
Iran relief location map.jpg
Green pog.svg
Tehran
Green pog.svg
Kerman
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UTC  time1981-06-11 07:24:25
ISC  event 625020
USGS-ANSS ComCat
Local dateJune 11, 1981 (1981-06-11)
Local time10:54:25 IRST
Magnitude6.6 Mw [1]
6.7 Ms [2]
Depth18 km (11 mi) [1]
Epicenter 29°55′N57°50′E / 29.91°N 57.83°E / 29.91; 57.83 [1]
Type Strike-slip and reverse [3]
Total damage$5 million [4]
Max. intensity MMI VIII (Severe) [5]
ForeshocksNo [3]
Casualties3,000 dead
1,400 injured [5]

The 1981 Golbaf earthquake struck the Iranian desert by the village of Golbaf on June 11 at 10:54:25 local time. The shock measured 6.6 on the moment magnitude scale, and had a surface-wave magnitude of 6.7. The shock had a maximum Mercalli intensity of VIII (Severe). Many villages were devastated and financial losses amounted to $5 million (in 1981 USD). Despite the sparsity of the area, 3,000 were killed and 1,400 were killed.

Contents

Tectonic setting

Eastern Iran is moving at a rate of approximately 15 mm (0.59 in)/yr with respect to Afghanistan. To accommodate this, the 600 km (370 mi) north-south trending Sabzevaran-Gowk-Nayband fault system began to develop in the western margin of the Dasht-e Lut. [6] [7]

The Gowk fault is a north-northwest trending fault that extends for over 150–180 km (93–112 mi) across the Lut Desert in Kerman Province, Iran. [3] [8] The fault moves dextrally and reverse, and has slipped at a rate of around 3.1–5.7 mm (0.12–0.22 in)/yr for the past 6-8 kyr. [i] [3] [9] [10] With a strike of 155 degrees, the Gowk fault does not orient itself parallel with the slip in the region. As a result, the Shahdad Thrust system takes up the shortening component of regional slip. [11] The Gowk fault is very active, generating multiple other destructive earthquakes such as the 1981 Sirch earthquake. [6] Despite this activity, a ~90–100 km (56–62 mi) segment in the south of the fault (Sarvestan segment) has remain unbroken, leading to a high potential hazard for future earthquakes. [6] [9]

Earthquake

The Mw 6.6, Ms 6.7 shock struck near the village of Golbaf at 10:54:25 local time. [1] [2] The earthquake had a maximum Modified Mercalli intensity of VIII (Severe). [5] The complex rupture extended across at least 15 km (9.3 mi) of the Gowk fault system. [12] An eastern segment slipped 3 cm (1.2 in) dextrally and 5 cm (2.0 in) vertically over a 14.5 km (9.0 mi) span. A western segment had little offset over a 7.5 km (4.7 mi) rupture, but fissured along its length. [3] These surficial displacements are far smaller than would be expected for an earthquake of this size, but this can be explained by the depth of the earthquake. [13] Average slip at depth was estimated to be 1.4 m (4 ft 7 in). [14] The earthquake led to a static stress increase of 3.4 bar on the southern Sarvestan segment of the Gowk fault. [15] Additionally, an increase of up to 2 bars to the north helped trigger the later 1981 Sirch earthquake. [16]

Aftershocks

The earthquake had a few mb 4+ aftershocks for the next couple weeks, but seismicity was not well recorded by teleseismic observations. [17] A month and a half after the mainshock, on July 28, the 1981 Sirch earthquake struck along the Gowk fault in a similar area. Despite nucleating in the same area, it ruptured in a completely different direction, with the rupture zones having no overlap. [18] It caused further destruction to the already severely damaged villages nearby, though killed much fewer people as the populace was living in tents after the original shock. [19]

Impact

The strong earthquake left 3,000 injured and 1,400 killed. [5] Every village in the Golbaf depression was devastated. [3] Losses were estimated at $5 million USD (in 1981 dollars). [4]

See also

Notes

  1. ↑ kyr = thousand years

References

  1. 1 2 3 4 International Seismological Centre. Bulletin of the ISC. Thatcham, United Kingdom.[Event  625020 ].
  2. 1 2 "M 6.7 - 73 km SE of Kerman, Iran". United States Geological Survey. Retrieved 26 June 2025.
  3. 1 2 3 4 5 6 Berberian et al. 1984, p. 814.
  4. 1 2 National Geophysical Data Center / World Data Service (NGDC/WDS) (1972). "Significant Earthquake Database" (Data Set). National Geophysical Data Center, NOAA. doi:10.7289/V5TD9V7K. Archived from the original on September 29, 2006.
  5. 1 2 3 4 Berberian 2014, p. 611.
  6. 1 2 3 Fattahi et al. 2014, p. 334.
  7. ↑ Walker & Jackson 2002, p. 1679.
  8. ↑ Walker et al. 2010, p. 222.
  9. 1 2 Walker et al. 2010, p. 221.
  10. ↑ Fattahi et al. 2014, p. 335.
  11. ↑ Walker & Jackson 2002, p. 1679-1680.
  12. ↑ Berberian et al. 1984, p. 809.
  13. ↑ Berberian et al. 2001, p. 389.
  14. ↑ Nalbant, Steacy & McCloskey 2006, p. 311.
  15. ↑ Nalbant, Steacy & McCloskey 2006, p. 312.
  16. ↑ Nalbant, Steacy & McCloskey 2006, p. 316.
  17. ↑ Berberian et al. 1984, p. 821.
  18. ↑ Berberian et al. 1984, p. 835.
  19. ↑ Berberian et al. 1984, p. 816-817.

Sources

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