1967 Mudurnu earthquake

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1967 Mudurnu earthquake
Turkey relief location map.jpg
Bullseye1.png
UTC  time1967-07-22 16:57:00
ISC  event 833573
USGS-ANSS ComCat
Local date22 July 1967 (1967-07-22)
Local time18:57
Magnitude7.4 Mw [1] 7.1 Ms [2]
Depth33.0 km [3]
Epicenter 40°40′N30°41′E / 40.67°N 30.69°E / 40.67; 30.69 [4]
Type Oblique slip
Areas affected Turkey
Max. intensity X (Extreme) [5]
Casualties86 dead

The 1967 Mudurnu earthquake or more correctly, the 1967 Mudurnu Valley earthquake occurred at about 18:57 local time on 22 July near Mudurnu, Bolu Province, north-western Turkey. [6] The magnitude 7.4 Mw [7] earthquake (but only 6.0 on the mb scale. [8] ) was one of a series of major and intermediate quakes that have occurred in modern times along the North Anatolian Fault since 1939. [9]

Contents

Earthquake

Although the Mudurnu Valley earthquake was relatively strong, there were only 86 fatalities, with 332 people injured. About 5,200 houses were destroyed or damaged beyond repair; [10] some 900 of these were in Adapazarı at the far western end of the fault zone, and many collapsed completely as a result of aftershocks. [11]

Intensity

The authors of the 1968 UNESCO report into the Mudurnu Valley earthquake, with Nicholas Ambraseys as its first author, felt that its Mercalli intensity was difficult to estimate accurately. In some places an implied level of XII (Extreme) was evident, whereas the vibrational effects were nearer VIII–IX (Severe–Violent). Although a large number of sites were independently assessed by up to six observers, variations of up to four degrees of the Mercalli scale indicated that an accurate figure was practically impossible to gauge. [12] A 1988 paper authored by Ambraseys lists the event with a maximum Mercalli intensity of X (Extreme). [5]

Damage

Considering the large surface-wave magnitude (7.1) and widespread surface rupturing, structural damage to buildings was surprisingly small; variations in damage were related to the materials used and construction method of individual buildings, rather than the proximity to the fault break. [13] Some villages suffered 70% destruction of property, while others nearby with fault lines running right through them had only a few houses damaged.

Surface rupture

The surface rupture zone, which was between 1–4 kilometres (0.62–2.49 mi) wide, stretched some 80 km (50 mi) from to Lake Abant (Turkish : Abant Gölü) to Sapanca in an East–West direction, generally following the course of the Mudurnu River until it flows north near Lake Sapanca. The earthquake is named after the river valley, not the town of Mudurnu itself, which is some distance south of the river and outside the rupture zone.[ citation needed ]

Aftershocks

A number of small aftershocks occurred, mostly towards the westward end of the fault zone; its eastern end overlapped the rupture zone of the previous M7.1 1957 Abant earthquake with a similar epicentre, by about 25 km (16 mi). [14]

See also

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References

  1. ↑ ANSS: Mudurnu 1967 (accessed 2018-04-05).
  2. ↑ Ambraseys et al. 1968, p. 14.
  3. ↑ ISC-EHB Event 833573 [ IRIS ].
  4. ↑ ISC-EHB Event 833573 [ IRIS ].
  5. 1 2 Ambraseys, N. N. (1988), "Engineering seismology: Part I", Earthquake Engineering & Structural Dynamics, 17 (1), Table IV, doi:10.1002/eqe.4290170101, ISSN   0098-8847
  6. ↑ Ambraseys et al. 1968 , p. 14.
  7. ↑ ANSS: Mudurnu 1967 .
  8. ↑ ISC-EHB Event 833573 [ IRIS ]. The difference is due to differences in what each scale measures.
  9. ↑ Toksöz, Shakal & Michael 1979 , p. 1261.
  10. ↑ Ambraseys et al. 1968 , p. 14.
  11. ↑ Ambraseys et al. 1968 , pp. 15, 43.
  12. ↑ Ambraseys et al. 1968 , p. 48.
  13. ↑ Ambraseys et al. 1968 , p. 42.
  14. ↑ Toksöz, Shakal & Michael 1979 , p. 1263; Ambraseys et al. 1968 , p. 49.

Sources

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