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Halide Nur Dursun | Dec 24, 2024
ITU Faculty of Mines Researchers continue to unravel the mysteries of 2023 Kahramanmaraş Earthquakes.
Supershear Triggering and Cascading Fault Ruptures of the 2023 Kahramanmaraş, Türkiye, Earthquake Doublet
In early 2024, within a strong collaboration with an international research team, Prof. Dr. Tuncay Taymaz and Reserach Assistant Ceyhun Erman from the Department of Geophysical Engineering published a very detailed article in the field of earthquake source seismology about the earthquakes that occurred in the Nurdağı-Pazarcık (Kahramanmaraş) region on 6 February 2023, which caused great damage and loss of life and had devastating effects on our national economy. The details of this interesting study are as follows:
Title: Supershear Triggering and Cascading Fault Ruptures of the 2023 Kahramanmaraş, Türkiye, Earthquake Doublet
Authors: Chunmei Ren, Zexin Wang, Tuncay Taymaz, Nan Hu, Heng Luo, Zeyan Zhao, Han Yue, Xiaodong Song, Zhengkang Shen, Haoyu Xu, Jianghui Geng, Wei Zhang, Teng Wang, Zengxi Ge, T. Serkan Irmak, Ceyhun Erman, Yijian Zhou, Zhen Li, Hang Xu, Bonan Cao, Hongyang Ding
Article Info: AAAS Science Magazine Volume 383 | Issue 6680 | pp. 305-311 | 19 January 2024 | DOI: 10.1126/science.adi1519
Summary— On 6 February 2023, two large earthquakes (moment magnitude 7.8 and 7.6) shocked a vast area of southeastern Türkiye and northern Syria, leading to heavy casualties and economic loss. To investigate the rupture process over multiple fault segments, we performed a comprehensive analysis of local seismic and geodetic data and determined supershear ruptures on the initial branch and the Pazarcık and Erkenek segments and subshear ruptures on the Amanos segment of event 1. The bilateral rupture of event 2 also presents distinct sub- and supershear velocities. The dynamic stress of the branch fault rupture triggered the Pazarcık segment initial rupture at a point 9 kilometers west of the junction of these two faults, boosting the supershear rupture of the Pazarcık segment of the main fault. The geometry and prestress level of multiple segments controlled the rupture behaviors and influenced the ground shaking intensity.
SCIENCE Editor’s Comment — In this study authors used an array of geophysical observations to determine how rupture propagated along the complex series of faults. The rupture speed was faster than the shear wave velocity at times, a condition called supershear. The authors pieced together some of the underlying physics behind this complex earthquake, helping us better understand the rupture process and subsequent ground shaking. — Brent Grocholski
Click here to access the article
Figure. Maps of faults and earthquakes in the region (Ren et al., 2024).
Figure. Coseismic deformation and slip models (Ren et al., 2024).
Figure. Analyses of event 1 rupture kinematics (Ren et al., 2024)
Figure. Stresses on the fault segments (Ren et al., 2024)
Authors left to right: (Front row) Zhengkang Shen, Han Yue, Haoyu Xu, Heng Luo, Zexin Wang, Chunmei Ren, Nan Hu, Zeyan Zhao, Xiaodong Song, Tuncay Taymaz; (Back row) T. Serkan Irmak, Jianghui Geng, Zhen Li, Bonan Cao, Hang Xu, Hongyang Ding, Yijian Zhou, Zengxi Ge, Teng Wang, Wei Zhang, Ceyhun Erman
Unexpected far-field deformation of the 2023 Kahramanmaraş earthquakes revealed by space geodesy
Later, in October 2024, the results of another interesting research on these earthquake doublets, in which Prof. Dr. Ziyadin Çakır from the Department of Geological Engineering participated as an author, were published in an article entitled "Unexpected far-field deformation of the 2023 Kahramanmaraş earthquakes revealed by space geodesy" in the journal SCIENCE.
More details on this article can be found below:
Title: Unexpected far-field deformation of the 2023 Kahramanmaraş earthquakes revealed by space geodesy
Authors: S. Ergintav, P. Vernant, O. Tan, H. Karabulut, S. Özarpacı, M. Floyd, A.Ö. Konca, Z. Çakır, D. Acarel, R. Çakmak, H. Vasyura-Bathke, U. Doğan , A. İ. Kurt 11, A. Özdemir , E. T. Ayruk, M. Turğut , Ö. Özel, İ. Farımaz
Article Info: AAAS Science Magazine Volume 386 | Issue 6719 | pp. 328-335 | 17 October 2024 | DOI: 10.1126/science.ado4220
Summary— The spatiotemporal pattern of surface displacements from large earthquakes provides crucial insights about the deformation of Earth’s crust at various scales and the interactions among tectonic plates. However, the lack of extensive and large-scale geodetic networks near such seismic events hinders our thorough understanding of the large-scale crustal deformation resulting from earthquakes. Using Türkiye’s extensive and continuous global navigation satellite system (GNSS) network during the moment magnitude 7.8 and 7.6 Kahramanmaraş earthquakes on 6 February 2023, we show that large earthquakes can induce far-field crustal deformations (>700 kilometers), exceeding current predictions from elastic dislocation models. They can lead to the mobilization of tectonic plates and the triggering of far-field earthquakes, which carries profound implications for seismic hazard assessments and necessitates a new perspective on crustal deformation and earthquake mechanics.
SCIENCE Editor’s Comment — Earthquakes deform the areas near the fault in a dramatic and devastating fashion. However, additional deformation occurs far from the fault over a longer timescale as the crust adjusts to the changes in stress. Ergintav et al. showed that this far-field deformation was much larger after the 6 February 2023 Kahramanmaraş earthquake sequence than expected. The large amount of far-field deformation has broad implications for the seismic hazard assessment of the region and may require rethinking the mechanics of some types of earthquakes. —Brent Grocholski
Click here to access the article
Figure. Co- and postseismic displacements and 95% confidence ellipses for Pazarcık (Mw 7.8) and Elbistan (Mw 7.6) events on 6 February 2023, using layered elastic half-space models (Ergintav et al., 2024).
Figure. The triggering of seismic activity in the far field (Ergintav et al. 2024).