Magnitude-5.9 quake strikes the eastern end of the North Anatolian Fault

By: Haluk Eyidoğan, Ph.D., Professor of Seismology, Istanbul Technical University
 

A moderate earthquake struck the Bingöl province in eastern Turkey on Sunday. The quake occurred at the intersection between two major faults in the region along a right-lateral strand of the North Anatolian Fault.
 

Citation: Eyidoğan, H., 2020, Magnitude-5.9 quake strikes the eastern end of the North Anatolian Fault, Temblor, http://doi.org/10.32858/temblor.095
 

On June 14, 2020 (14:26 UTC) in the province of Bingöl in eastern Turkey, near Kaynarpinar village (39.3495 N, 40.7350 E), a strong earthquake occurred. According to Turkish authorities, the shallow — 3.1 mile (5 kilometer) — deep quake registered as a magnitude-5.8. The European Mediterranean Seismic Centre (EMSC) reports it as a magnitude-5.9.

 

 

The number of buildings damaged in the quake is not currently known, but there are reports of significant damage to mudbrick masonry structures and also to a small number of reinforced concrete structures. Official statements report at least one fatality and several people injured.

 

Junction of the North Anatolian and East Anatolian Faults

The earthquake ocurred where the North Anatolian Fault and the East Anatolian Fault meet. This junction exhibits a rather complicated network of faults of different length that cross one another. Depending on the orientation and magnitude of stress imparted by this earthquake on the faults in the region, I expect that aftershock activity may be prolonged.

 

Elmali Fault a likely source

The earthquake seems to have struck on the right-lateral strike-slip Elmalı Fault, a 27-kilometer-long branch of the North Anatolian Fault, based on the latest official active fault map in Turkey. Slip on this fault caused a magnitude-6.9 earthquake on August 17, 1949. Regions of high damage correlate to the location of the Elmalı Fault, further suggesting this is the structure that ruptured. The locations of large and moderate magnitude earthquakes are often revised by scientists after review of available data. After the location of this earthquake is revised and finalized, the quake’s relationship with the 40-kilometer-long Kargıpazar Fault, parallel to the Elmalı Fault, will be better understood.

 

After 250 years of quiet, is the Yedisu Fault now in play?

The epicenter of the earthquake is located near the eastern end of the Yedisu Fault, one of the important segments of the North Anatolian Fault. The Yedisu Fault has not generated a strong earthquake in the last 250 years — since 1874, when a magnitude-5.8 quake struck — according to current records. Given the location of this week’s earthquake and the orientation of the fault that likely ruptured, I recommend calculating how much stress the 1874 earthquake — with a right strike-slip fault mechanism — loaded on Yedisu Fault. This analysis may inform futures estimates of earthquake hazard in the region.

 

Further Reading

Active Faults of Turkey, General Directorate of Mineral Research and Exploration (MTA), Ankara, Turkey.
Duman, T.Y. & Emre, Ö., 2013. The East Anatolian Fault: geometry, segmentation and jog characteristics Geological Society, London, Special Publications, 372, 495-529.

Eyidoğan, H., U. Güçlü, Z. Utku & E. Değirmenci, 1991. Türkiye büyük depremleri makro-sismik rehberi (1900-1988), İstanbul Teknik Üniversitesi, İstanbul, 199 pages.

http://www.koeri.boun.edu.tr/sismo/2/latest-earthquakes/list-of-latest-events/

https://www.emsc-csem.org/Earthquake/earthquake.php?id=867603#summary