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The 2023 Mw7.8 Kahramanmaraş, Turkey Earthquake: A Multi-segment Rupture in Millennia Supercycle

Liuwei Xu, Saeed Y. Mohanna, Lingsen Meng, Chen Ji, Jean-Paul Ampuero, Zhang Yunjun, Masooma Hasnain, Risheng Chu, & Cunren Liang

Submitted September 10, 2023, SCEC Contribution #12938, 2023 SCEC Annual Meeting Poster #030

An Mw 7.8 earthquake occurred on the East Anatolian Fault (EAF) and the secondary Narlı Fault (NF) on Feb 6, 2023, closely followed by an Mw 7.5 event on the Sürgü Fault 9 hours later. We analyze the distant and local seismic data, high-rate GNSS recordings, and radar satellite images by Slowness Enhanced Back-Projection and joint Finite Fault Inversion for the Mw 7.8 event to resolve its rupture process. The rupture first initiates and propagates on the NF. After reaching the junction with the EAF, it propagates bilaterally on the EAF, extending 120 km to the northeast at 3.05 km/s and 200 km to the southwest at 3.11 km/s. The southwest speed is verified by local seismic recordings and the absence of Mach surface wave characteristics. Compared with the EAF, the NF features denser seismic activity in recent decades, suggesting that it was more favorable for rupture nucleation. The EAF segments where the largest coseismic slip occurred have been relatively quiescent since the late 1800s. But the slip is much larger than the long-term accumulation during this period, being attributed to ≥900 year supercycle. The EAF geometry is similar to the San Andreas Fault (SAF) and San Jacinto Fault (SJF). Considering high slip rates and the lack of large earthquakes on their southern segments since 1857, an M8 earthquake could potentially occur there.

Xu, L., Mohanna, S. Y., Meng, L., Ji, C., Ampuero, J., Yunjun, Z., Hasnain, M., Chu, R., & Liang, C. (2023, 09). The 2023 Mw7.8 Kahramanmaraş, Turkey Earthquake: A Multi-segment Rupture in Millennia Supercycle. Poster Presentation at 2023 SCEC Annual Meeting.

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