Central Anatolian Fault

Central Anatolian Fault
Name	Central Anatolian Fault
Location	Central Anatolia, Turkey
Type	Strike-slip fault
Length	~300 km
Plate	Anatolian Plate
Movement	Right-lateral

Central Anatolian Fault The Central Anatolian Fault is a major right-lateral strike-slip structure in central Turkey linking the tectonics of Anatolia, the East Anatolian Fault, and the North Anatolian Fault. It accommodates lateral motion between the Anatolian Plate and surrounding plates, influencing seismicity near Sivas, Kayseri, and Yozgat. The fault system intersects with volcanic and basin provinces such as the Cappadocia region and affects infrastructure corridors including routes between Ankara and Erzincan.

Overview

The Central Anatolian Fault traverses the heartland of Turkey, crossing provinces like Kırşehir, Nevşehir, and Yozgat while interfacing with topographic features including the Taurus Mountains and the Pontic Mountains. It forms part of a diffuse shear zone related to the collision of the Arabian Plate with the Eurasian Plate and the westward escape of Anatolia after interactions with the Hellenic Trench and the Cyprus Arc. The fault's activity has implications for regional centers such as Kayseri Erciyes Airport and cultural sites in Cappadocia.

Tectonic Setting and Geology

The fault lies within a complex tectonic mosaic shaped by convergence at the Bitlis-Zagros Thrust and oblique collision along the Aegean Sea margin. Lithologies adjacent to the fault include Mesozoic carbonates exposed in the Tethys Ocean margin sequences and Neogene volcanics associated with Erciyes Volcano and Hasan Dağı. The regional stress regime is modulated by interactions with structures like the Sivas Basin, the Central Anatolian Plateau, and the Ankara-Erzincan Fault system. Ophiolitic fragments from the Pontides and nappes emplaced during the closure of the Tethys Ocean influence fault rheology and rupture propagation.

Fault Geometry and Segmentation

The Central Anatolian Fault is segmented into multiple strands with stepovers and releasing bends that partition slip among subsidiary faults approaching the East Anatolian Fault junction. Key segments align near towns such as Aksaray and Çorum, and geometric complexities occur at relay zones adjacent to the Kızılırmak River valley. Structural mapping reveals strike-slip shear zones, pull-apart basins, and transpressional uplifts comparable to features on the North Anatolian Fault and along the Dead Sea Transform. Detailed mapping campaigns reference seismic reflection profiles across the Sakarya Zone and across Cenozoic sedimentary basins.

Seismicity and Historical Earthquakes

Instrumental and historical records attribute moderate to large earthquakes to the Central Anatolian Fault, impacting urban centers such as Sivas and Kayseri. Paleoseismic trenching near archeological sites in Çatalhöyük and Aşıklı Höyük provides constraints on recurrence intervals alongside cataloged events recorded by the Ottoman Empire and observatories in Istanbul and Ankara. Earthquake sequences on neighboring systems—including the 1939 Erzincan earthquake and the 1999 İzmit earthquake on the North Anatolian Fault—illustrate regional stress transfer that may influence rupture on this fault.

Geodetic Studies and Slip Rates

Satellite geodesy using Global Positioning System arrays, InSAR campaigns, and leveling across central Turkey estimate right-lateral slip rates that vary along strike and are lower than rates on the North Anatolian Fault and East Anatolian Fault. Continuous GNSS stations operated by institutions like General Directorate of Mapping (Turkey) and regional universities record crustal velocities tied to models of plate interactions. Geodetic strain accumulation across the Central Anatolian Fault contributes to assessments of seismic potential when combined with paleoseismic offsets measured in trenches and geomorphic markers along the Kızılırmak terraces.

Hazard Assessment and Risk Mitigation

Hazard models for central Turkey incorporate fault geometry, slip rates, and seismic history to produce shaking scenarios for population centers including Ankara and Kayseri. Lifelines such as the Ankara–Sivas railway and highways crossing fault zones are evaluated in vulnerability studies coordinated with municipal authorities and emergency agencies like the Disaster and Emergency Management Presidency (AFAD). Mitigation strategies reference seismic building codes promulgated after the 1999 events, retrofitting programs for heritage sites such as Cappadocia cave dwellings, and urban planning measures in provincial capitals like Kırşehir.

Research and Monitoring Efforts

Ongoing interdisciplinary research involves paleoseismology at trench sites near archaeological localities, seismic arrays operated by universities including Middle East Technical University and Boğaziçi University, and remote sensing studies using data from satellites such as Sentinel-1 and missions managed by European Space Agency. Collaborative projects link Turkish institutions with international bodies like the United States Geological Survey and the International Seismological Centre to improve catalogs, early warning potential, and community resilience training programs in affected provinces. Continued funding and coordination aim to refine rupture forecasts, expand GNSS coverage, and integrate geologic, geodetic, and seismic datasets for comprehensive hazard models.

Category:Geology of Turkey Category:Seismic faults of Asia