Turkey

Turkiye (Turkey) is one of the world's most seismically dangerous nations, host to two of the planet's most active and hazardous fault systems. The North Anatolian Fault (NAF) is a 1,500-kilometre right-lateral strike-slip fault that runs east-west across northern Turkey from the Karliova Triple Junction near Erzincan to the northern Aegean Sea — among the world's best analogues to the San Andreas Fault in California. The East Anatolian Fault (EAF), also a major left-lateral strike-slip boundary, runs from the same Karliova junction southwestward to the Gulf of Iskenderun, forming the tectonic boundary between the Anatolian Plate and the Arabian Plate. Between these two faults, the Anatolian Plate is being extruded westward at 20–30 millimetres per year, escaping from the squeeze of the Arabia-Eurasia collision. Western Turkey is dominated by north-south oriented extensional [[fault]] systems that have created a dramatic graben-horst landscape including the Gediz and Büyük Menderes grabens and the Izmir Bay.

Turkey's earthquake history is among the most devastating in the 20th and 21st centuries. The 1939 Erzincan earthquake (magnitude 7.8) killed approximately 32,000 people in the city and triggered a cascade of major events along the NAF — a westward migrating earthquake sequence that continued through 1967. The 1999 Izmit earthquake (magnitude 7.6, also called Kocaeli earthquake) killed over 17,000 people in the densely industrialised Marmara region and caused economic damage exceeding $20 billion. Three months later, the 1999 Düzce earthquake (magnitude 7.2) struck the same region. The 2011 Van earthquake (magnitude 7.1) killed 604 people in eastern Turkey. In February 2023, the Kahramanmaras earthquake sequence struck with a magnitude 7.8 mainshock followed nine hours later by a magnitude 7.7 event on a different fault segment. These two earthquakes killed over 50,000 people in Turkey and Syria, destroyed more than 300,000 buildings, and constituted the deadliest earthquake sequence in Turkey's modern history and one of the deadliest globally in the 21st century. [[aftershock]] sequences from Turkish earthquakes frequently include multiple damaging events over extended periods.

The tectonic context of Turkey's seismicity reflects its unique position as a wedge of continental crust being expelled westward from the Arabia-Eurasia collision. The Anatolian Plate is not a true independent plate but a continental block moving approximately 20 mm/yr westward relative to Eurasia, driven by the northward push of the Arabian Plate and the gravitational pull of the Hellenic subduction trench in the Aegean. The NAF is one of the world's most geomorphologically impressive active faults, with clear linear traces, offset drainage systems, and pressure ridges visible from satellite imagery. Its history of westward-migrating earthquake sequences raises the concern that the western section — now approaching Istanbul — may be the next to rupture. Paleoseismic studies suggest a recurrence interval of 200–400 years for major NAF earthquakes, and segments near Istanbul appear to have last ruptured in the 1766 earthquake. The [[seismic-wave]] propagation across Turkey is well-recorded by the dense AFAD national network, providing an exceptional dataset for hazard research and [[early-warning]] system development.