SEISMOTECTONIC IMPLICATIONS OF THE 2023.02.06 KAHRAMANMARAS EARTHQUAKES (M7.8 AND M7.5) AND THEIR AFTERSHOCKS, SOUTHEAST TURKIYE

On 2023.02.06, two devastating earthquakes (M7.8 and M7.5) occurred nine hours apart and their aftershocks turned into a disaster affecting many settlements in southeastern Türkiye and Syria, killing tens of thousands of people. In this study, we analyze the surface deformation during earthquakes and its regional seismotectonic meaning together with seismological data.

We were able to map the surface rupture of the 2023.02.06 Kahramanmaraş earthquakes with the help of field studies and post-earthquake sub-meter-resolution Göktürk satellite imagery and aerial photographs available on the General Directorate of Mapping's Küre application and Worldview satellite imagery shared by Maxar Technologies. During these earthquakes, the surface rupture occurred on two different fault systems:

(1) the overall northeast-southwest trending surface rupture caused by the 2023.02.06 M7.8 and M6.8 earthquakes is about 300 km long, from east of Çelikhan to northeast of Hatay city center. Along this line, the maximum left-lateral offset seen in the images is roughly 6.5 m. North of Pazarcık, between Gölbaşı and Türkoğlu, a 35 km long NNE-SSW trending rupture merges with the main NE-SW surface rupture just northeast of the main shock. This junction is important for understanding the structural relationship between the Dead Sea Fault Zone (DSFZ) and the Eastern Anatolian Fault Zone (EAFZ). The NNE-SSW trending left-lateral segment, which we call the Kadıncık Fault, cross-cuts the Evri Quaternary pull-apart basin and is the northernmost end of the DSFZ. It forms a junction with the NE-SW trending surface rupture of the EAFZ north of Pazarcık.

(2) the 2023.02.06 M7.5 earthquake, which occurred nine hours after the first main shock, caused an almost east-west trending surface rupture extending from Göksun to the northeast of Doğanşehir. Its entire length is about 135 km and the largest left-lateral offset measured in the images is about 8.5 m. This rupture was formed on the Çardak Fault, which is shown on the Active Fault Map of Türkiye. This fault, together with the Sürgü Fault immediately to the east, is part of the Anatolian Diagonal system, which we defined as a large left-lateral shear zone extending from central-eastern Anatolia to Cyprus in our recently published study.