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WITHDRAWN February 6, 2023 Kahramanmaraş Earthquake Sequence: Preliminary Observations Along the Surface Rupture and Slip Distribution of the Mw7.5 Ekinözü Earthquake

The 6 February 2023 Kahramanmaraş earthquake sequence started with a magnitude 7.8 (USGS) earthquake at 4:17 a.m. local time with epicentral coordinates of 37.288 N, 37.043 E. This earthquake was initiated along the Narli fault and propagated onto the tectonic boundary between the Anatolian and Arabian plates, rupturing it bilaterally for over 300 km. This earthquake was followed by a magnitude 7.5 (USGS) at 1:24 p.m. local time, with the epicenter near Ekinozu (38.089°N, 37.239°E). The Ekinözü earthquake also ruptured bilaterally and resulted in approximately 140 km of co-seismic surface rupture. Field investigations supplemented with interpretations of high-resolution sUAS (small unmanned aircraft systems) and helicopter images together with USGS-led interpretations of high-resolution optical imagery from WorldView 1-3satellites (© 2023 Maxar) show that the surface rupture occurred on two different left-lateral strike faults: The first, known as the Çardak fault, extends from the town of Göksun in the west to Bıçakçı village in the east. The second is the newly-named Çığlık Fault, a NE-SW-striking left-lateral fault that does not have a strong geological or a geomorphological imprint before this earthquake.

The surface trace of the Çardak Fault can be divided into two geometric sections: The arc-shaped western section extends between Göksun and Nurhak for nearly 80 km. Slip along the eastern half of this section was typically over 6 meters, reaching over 8 meters at the maximum slip location east of the epicenter. The second fault section extends nearly E-W between Nurhak and Bıçakçı for almost 20 km. The average of slip measurements along this linear section of the Çardak fault is around 2.5 m. Our field investigations indicate the rupture established a new trend after Bıçakçı instead of utilizing the E-W-oriented Sürgü Fault. The average slip along this new 40 km-long fault zone, here named Çığlık fault, is about 1m, with maximum left-lateral slip reaching ~2.5m.

Session: February 2023 Mw 7.8 Earthquake Sequence in Turkey

Type: Oral

Room: 201 A/B

Date: 4/19/2023

Presentation Time: 10:30 AM (local time)

Presenting Author: Sinan O. Akçiz

Student Presenter: No

Additional Authors