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

• Published in: Nature communications 2023-09, Vol.14 (1), p.5564-5564, Article 5564
• Main Authors: Liu, Chengli, Lay, Thorne, Wang, Rongjiang, Taymaz, Tuncay, Xie, Zujun, Xiong, Xiong, Irmak, Tahir Serkan, Kahraman, Metin, Erman, Ceyhun
• Format: Article
• Language: English
• Subjects: 704/2151/508; 704/2151/562; 704/4111; Aftershocks; Earthquake damage; Earthquakes; Fault lines; Geological faults; Humanities and Social Sciences; Kinematics; multidisciplinary; Rupture; Rupturing; Satellite observation; Science; Science (multidisciplinary); Seismic activity
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-41404-5

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. Kinematic models for the two major earthquakes on February 6, 2023 along the East Anatolian Fault Zone reveal complex multi-fault rupture and the plausible triggering of the doublet aftershock by the first event. (*couldn’t find author-written summary)