East Anatolian Fault

East Anatolian Fault
Roxy · CC BY-SA 3.0 · source
Name	East Anatolian Fault
Type	Strike-slip fault
Location	Eastern Anatolia, Turkey
Length	~700 km
Plate boundaries	Anatolian Plate, Arabian Plate
Motion	Left-lateral

East Anatolian Fault The East Anatolian Fault is a major left-lateral strike-slip fault zone in eastern Turkey that accommodates relative motion between the Anatolian Plate and the Arabian Plate, connecting with the Dead Sea Transform system and interacting with the North Anatolian Fault, the Bitlis-Zagros thrust belt, and the Aegean extensional province. It lies near provinces and cities such as Erzincan, Diyarbakır, Malatya, and Gaziantep and has been a focus for research by institutions including the General Directorate of Mineral Research and Exploration, Kandilli Observatory and Earthquake Research Institute, and international teams from USGS, GFZ German Research Centre for Geosciences, and various universities.

Geology and Tectonic Setting

The fault forms part of the continental transform network that transfers convergence from the Arabian Plate–Eurasian Plate collision into lateral escape of the Anatolian Plate, linking the Dead Sea Transform to the west and stepping toward the East African Rift and the Caucasus orogenic system. Regional geology comprises Mesozoic and Cenozoic sedimentary basins such as the Seyhan Basin, volcanic provinces like the Sultansazlığı volcanic field, and metamorphic units associated with the Pontides and Tauride Belt; these lithologies control fault localization and rheology studied in work by teams from Istanbul Technical University, Middle East Technical University, and Boğaziçi University.

Fault Geometry and Segmentation

The fault traces a complex, ~700 km sinuous corridor with major segments conventionally named for adjacent cities and basins (e.g., Erzinjan Segment, Pütürge Segment, Çelikhan Segment), linking with splays toward the Karasu River and stepping through pull-apart basins and restraining bends near Keban Reservoir and the Fırat (Euphrates) River. Detailed mapping by the Turkish Chamber of Geological Engineers, remote sensing by ESA and NASA satellites, and seismic reflection profiles reveal strike changes, stepovers, and branching that control rupture propagation and segment interaction along the corridor between the East Anatolian Fault and the North Anatolian Fault.

Seismicity and Historical Earthquakes

Instrumental seismicity recorded by networks such as the KOERI Seismic Network, USGS National Earthquake Information Center, and European-Mediterranean Seismological Centre shows frequent moderate events and episodic large earthquakes, including historically documented ruptures affecting cities like Elazığ, Kahramanmaraş, and Adıyaman. Historical catalogs compiled with archival sources, Ottoman chronicles, and paleoseismic trenching link major events to segments observed in 1789, 1872, and significant 20th–21st century earthquakes that produced surface rupture, intense shaking, and secondary effects impacting infrastructure projects such as the Birecik Dam and transport corridors to Istanbul and Ankara.

Slip Rates and Paleoseismology

Geodetic studies using GPS networks, campaign measurements coordinated by UNAVCO partners, and InSAR analysis from Sentinel-1 and RADARSAT indicate left-lateral slip rates typically on the order of a few mm/yr, with variations along-segment; these rates reconcile with long-term displacement inferred from trenching studies, radiocarbon dating, and offset geomorphic markers in alluvial fans and river terraces near the Zagros Thrust Front and Taurus Mountains. Paleoseismological investigations by teams from Carnegie Institution, University of Oxford, and Turkish universities have identified multiple prehistoric surface-rupturing events, recurrence intervals, and coseismic offsets that constrain seismic cycle models and inform rupture scenario catalogs used by EMSC and national hazard agencies.

Hazard Assessment and Risk Mitigation

Seismic hazard assessments integrate probabilistic seismic hazard modeling developed by groups at Earthquake Engineering Research Institute, Risk Management Solutions, and national agencies with exposure data for urban areas such as Diyarbakır and critical lifelines including pipelines, the Ankara–Baghdad railway, and hydroelectric installations. Building-stock vulnerability studies, retrofit programs led by municipal authorities and NGOs, and emergency response planning coordinated with AFAD and international partners focus on earthquake-resilient design, land-use regulation around active traces, and early-warning initiatives leveraging regional networks and international collaborations with Japan International Cooperation Agency and USAID-funded projects.

Monitoring and Research Studies

Continuous seismic and geodetic monitoring is conducted by facilities including Kandilli Observatory, regional arrays supported by IRIS, and satellite missions from ESA and NASA; research topics include dynamic rupture modeling, coulomb stress transfer between the East Anatolian Fault and North Anatolian Fault, paleoseismic trenching, fault-zone structure from seismic tomography studies by ETH Zurich and GFZ, and multiphysics simulations by teams at MIT, Caltech, and regional universities. International workshops and data-sharing initiatives hosted by ISC, UNESCO, and regional science bodies have advanced understanding of rupture propagation, site amplification in basins like the Dicle Basin, and integrated risk-reduction strategies deployed in southern and eastern Turkey.

Category:Seismic faults of Turkey