Tectonic Duets: Self-Similar Approach to Investigate Eastern Anatolian Fault’s Recent Seismicity, with Special Emphasis on the 6 February 2023 Earthquake Doublet

Abstract

Earthquake clusters possess profound potential for discerning antecedent seismic cues. This study examines the self-similarity of earthquakes to characterize recent seismic patterns in the prolonged quiescent Eastern Anatolian fault zone (EAFZ). We thoroughly investigate the correlation fractal dimension (Dc) formulated upon the scale-invariant relative clustering in earthquake pattern identification. We provide a comprehensive examination of pre- and postseismicity patterns of the Mw 7.7 Nurdağı-Pazarcık, Mw 7.6 Ekinözü, and Mw 6.7 Elazığ earthquakes, each shattering different segments of the EAFZ. The spatiotemporal fluctuations of Dc suggest the commencement of the preparatory process observed around October 2021 to February 2022 for the 2023 dual catastrophe, whereas in the case of the Mw 6.7 Elazığ, this was witnessed from November 2018. Prior to the 2023 events, low-moderate Dc regions predominated on the Pazarcık segment and Cardak fault. The Pürtürge segment that ruptured with an Mw 6.7 event was within a low Dc area. We identified a consistent relationship between stress levels and Dc for the 2023 twin events and the Mw 6.7 earthquake, with low Dc indicative of high stress. Intriguingly, mainshocks and a substantial proportion of their aftershocks have occurred within areas characterized by low to moderate Dc. Various fault zones like Malatya, Amanos, and Adiyaman are situated in areas with low Dc. The southwestern area of the Amanos segment exhibits clustering, elevated stress levels, and low Dc, followed by the Mw 7.7. Therefore, it is imperative to maintain vigilant monitoring of this region to prevent another disaster.