Title : Geodynamics and seismicity of the Anatolian-Caucasian-Arabian region and the earthquake in Turkey on February 6, 2023
Abstract:
A magnitude 7.8 earthquake occurred in southeastern Turkey on February 6, 2023. The earthquake's location is associated with the triple junction of the Anatolian, Arabian, and African plates and is confined to the East Anatolian Fault, which forms the boundary between the Anatolian and Arabian plates. The North Anatolian Fault separates the Eurasian and Anatolian tectonic plates, which slide relative to each other at a rate of 2 cm per year. Earthquakes occur regularly along this fault, and activity is gradually shifting further west, into the Sea of ??Marmara, toward Istanbul. The segment of this zone adjacent to the city has not been active for 250 years. The development of geodynamic models of the deep structure of disaster-prone areas is an important contribution to the study of active continental margins, which is necessary for earthquake prevention, prediction, and forecasting, geoecological risk assessment, and disaster preparedness.
The geodynamic model of the Anatolian-Caucasian-Arabian region is determined by mantle flow rising from the core surface and propagating beneath the lithosphere, creating complex surface velocities in Anatolia to the west, in the Arabian Plate to the east, and in the Caucasus to the north. This flow will continue to transport material along the North Anatolian and East Anatolian Faults. The frequency of strong earthquakes varies along the faults, due to the varying crustal thickness and rheology of the fault environment. The Moho depth of the East Anatolian Fault is approximately 40 km, while that of the North Anatolian Fault is approximately 50 km. Along the North Anatolian Fault, strong earthquakes occur every 1-10 years (1939, 1942, 1943, 1944, 1953, 1957, 1966, 1967, 1971, 1992, 1999) with hypocenters spaced approximately 100 km apart and pointing west. Since the 1999 Izmit earthquake occurred 80 km east of Istanbul, an earthquake in the Istanbul area can be expected within a few years (1-10 years).
Because the East Anatolian Fault produced strong earthquakes in 1789 (M 7.2), 1795 (M 7.0), 1872 (M 7.2), 1874 (M 7.1), 1875 (M 6.7), 1893 (M 7.1), 2020 (M 6.8), and 2023 (M 7.8, M 7.7). Therefore, the recurrence interval of these groups (1790–1880–2020) is approximately 100 years. However, within these groups, there are typically 2–4 strong earthquakes occurring close in time. It can be predicted that a strong earthquake on the East Anatolian Fault, if not occurring within 1–2 years, will occur only in 100 years.
