1969 Alaşehir earthquake

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1969 Alaşehir earthquake
1969 Alaşehir earthquake is located in Turkey
1969 Alaşehir earthquake
UTC time1969-03-28 01:48:32
ISC event811616
USGS-ANSSComCat
Local dateMarch 28, 1969 (1969-03-28)
Local time03:48:32
Magnitude6.6 Ms(ISC-GEM) 
Depth1.9 km[1]
Epicenter38°30′54″N 28°32′46″E / 38.515°N 28.546°E / 38.515; 28.546Coordinates: 38°30′54″N 28°32′46″E / 38.515°N 28.546°E / 38.515; 28.546
Areas affectedTurkey
Max. intensityMSK-64 VIII (Damaging)[2]
Casualties53 dead

The 1969 Alaşehir earthquake occurred on March 28, at 03:48 local time near the city of Alaşehir in Turkey's Manisa Province. The 6.6 Ms  earthquake struck at a depth of 1.9 km. It had a MSK 64 intensity of VIII (Destructive).[3] At least 53 people were killed in the earthquake.[4]

Tectonic setting[]

The Alaşehir region is dominated by extensional faulting in the young sedimentary layers. Extension accommodated by normal faults cause uplift in the land, forming graben features. Earthquakes in this region have pure normal dip-slip mechanism with no strike-slip components. These earthquakes occur along faults that are parallel to the grabens. Faults in the area have a dip angle of 30–60° and are up to 12 km beneath the surface.

Earthquake[]

The earthquake occurred in the Alaşehir Valley where normal faulting was the mechanism; occurring along a northwest–southeast striking, northeast dipping plane. Surface ruptures developed in the valley where the quake struck. At least six surface ruptures were traced uninterrupted for long distances. The longest rupture was measured at more than 12 km in length. The total length of measured surface rupture was 30–36 km, extending from Dereköy, through Alaşehir and terminating at Doğuşlar. An average surface offset of 20 cm was measures, although this was taken a week after the quake hence aseismic creep may have occurred and affected actual coseismic offset measurements.[5]

Rather unusual was the recording of one aftershock of mb  4.6 occurred. Felt report of aftershocks have been debunked as reports further north in Demirci, where another severe earthquake occurred on March 23.[5]

Impact[]

Land failure and landslides on the slopes of the valleys contributed to heavy damage. 3,072 buildings were damaged or destroyed.[6]> The Demirköprü Dam however, was undamaged. Many small villages suffered great destruction. A total of 53 people died.[4][3]

See also[]

References[]

  1. ^ International Seismological Centre. Event Bibliography. Thatcham, United Kingdom. [Event 189275].
  2. ^ B. Eravcı; C. Erkmen; M. Yaman; B. Tüzel; Y. Iravu (2009). "The Origin of Ground Deformations that Caused Damage at Sarigol-Manisa -Turkey". Geophysical Research Abstracts. European Geosciences Union. 11.
  3. ^ a b "28 MART 1969 MANİSA DEPREMİ" (in Turkish). AFAD. Retrieved 5 January 2022.
  4. ^ a b "Significant Earthquake Information". ngdc.noaa.gov. NOAA National Centers for Environmental Information. Retrieved 5 January 2022.
  5. ^ a b Haluk Eyidoğan; James Jackson (1985). "A seismological study of normal faulting in the Demirci, Alaşehir and Gediz earthquakes of 1969–70 in western Turkey: implications for the nature and geometry of deformation in the continental crust". Geophysical Journal International. 81 (3): 569–607. doi:10.1111/j.1365-246X.1985.tb06423.x.
  6. ^ "Important earthquakes in Turkey in 1900-2004 that have caused casualties and damage (Ms > 5.0)". koeri.boun.edu.tr (in Turkish). Kandilli Observatory. Retrieved 6 January 2022.

External links[]

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