Complex multi-fault rupture and triggering during the 2023 earthquake doublet in southeastern Türkiye

Chengli Liu; Thorne Lay; Rongjiang Wang; Tuncay Taymaz; Zujun Xie; Xiong Xiong; Tahir Serkan Irmak; Metin Kahraman; Ceyhun Erman

doi:10.1038/s41467-023-41404-5

Complex multi-fault rupture and triggering during the 2023 earthquake doublet in southeastern Türkiye

Nat Commun. 2023 Sep 9;14(1):5564. doi: 10.1038/s41467-023-41404-5.

Authors

Chengli Liu¹, Thorne Lay², Rongjiang Wang^{3

4}, Tuncay Taymaz⁵, Zujun Xie³, Xiong Xiong³, Tahir Serkan Irmak⁶, Metin Kahraman⁷, Ceyhun Erman⁵

Affiliations

¹ School of Geophysics and Geomatics, China University of Geosciences, Wuhan, Hubei, China. liuchengli@cug.edu.cn.
² Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA, USA.
³ School of Geophysics and Geomatics, China University of Geosciences, Wuhan, Hubei, China.
⁴ GFZ German Research Centre for Geosciences, Potsdam, Germany.
⁵ Department of Geophysical Engineering, The Faculty of Mines, Istanbul Technical University, Maslak 34467, Sarıyer, Istanbul, Turkey.
⁶ Department of Geophysical Engineering, Kocaeli University, 41380, Umuttepe, Kocaeli, Turkey.
⁷ Eurasian Institute of Earth Sciences, Istanbul Technical University, Maslak 34467, Sarıyer, Istanbul, Turkey.

Abstract

Two major earthquakes (M_W 7.8 and M_W 7.7) ruptured left-lateral strike-slip faults of the East Anatolian Fault Zone (EAFZ) on February 6, 2023, causing >59,000 fatalities and ~$119B in damage in southeastern Türkiye and northwestern Syria. Here we derived kinematic rupture models for the two events by inverting extensive seismic and geodetic observations using complex 5-6 segment fault models constrained by satellite observations and relocated aftershocks. The larger event nucleated on a splay fault, and then propagated bilaterally ~350 km along the main EAFZ strand. The rupture speed varied from 2.5-4.5 km/s, and peak slip was ~8.1 m. 9-h later, the second event ruptured ~160 km along the curved northern EAFZ strand, with early bilateral supershear rupture velocity (>4 km/s) followed by a slower rupture speed (~3 km/s). Coulomb Failure stress increase imparted by the first event indicates plausible triggering of the doublet aftershock, along with loading of neighboring faults.