North Anatolia lies across the mainly transform boundary between the Anatolian Plate and the Eurasian Plate. Relative to the Eurasian Plate the Anatolian Plate is being forced westwards by the continuing northward movement of the Arabian Plate. This motion is accommodated by a major dextral (right lateral) strike-slip fault system the North Anatolian Fault. This long structure extends from the Karlıova Triple Junction in the east to the Sea of Marmara in the west. In detail the fault is formed of many separate segments. Movement on parts of this fault zone have been responsible for many large and damaging earthquakes. They tend to form overall westward propagating sequences that can last for many decades. The most recent sequence began with the 1939 Erzincan earthquake, continuing with major earthquakes in 1942, 1943, 1944, 1949, 1951, 1957, 1966, 1967, 1992 and two in 1999.