Seismic Potential and Creep Analysis of the Pütürge Segment (Eastern Anatolian Fault Zone): Insights from SAR Interferometry for the 2020 Mw 6.8 Elazığ and 2023 Mw 7.8 Kahramanmaraş Earthquakes

On January 24, 2020, the Mw 6.8 Elazığ earthquake occurred on the Eastern Anatolian Fault (EAF) at the indentation zone where the Arabian Plate converges with the Anatolian Plate. It was one of the largest earthquakes on the EAF in the last century before the devastating February 6, 2023, Mw 7.8 and Mw 7.6 doublet earthquakes, separated by ~9 hours. The 2023 Mw 7.8 Kahramanmaraş mainshock propagated along a splay of the EAF, while the 2020 Elazığ earthquake originated near Lake Hazar and propagated southeast to the northern termination of the Pütürge segment. These events suggest the Pütürge segment remained locked during the 2020 and 2023 earthquakes.

This study analyzes the pre-seismic and postseismic deformation of the 2020 Mw 6.8 Elazığ earthquake using Sentinel-1 SAR interferometry to assess the seismic potential of the ~40 km long Pütürge segment and the northeastern EAF zone. We employ small baseline (SBAS) inversion algorithms to analyze time series data from ascending tracks (AT116, AT43) and descending tracks (DT123, DT21), using 402, 96, and 321 interferograms, respectively, for the postseismic phase, and ~1100 interferograms for the pre-seismic phase (2015–2020). We process geocoded unwrapped interferograms, correct errors, reduce tropospheric phase delays using ECMWF ERA5 products and estimate average velocities.

Our results reveal postseismic creep of up to ~25 mm/yr propagating towards the Pütürge segment, while minimal creep was observed in the descending track during the pre-seismic phase of the Mw 6.8 Elazığ earthquake. The faults responsible for the February 6, 2023, Mw 7.8 and Mw 7.6 earthquakes remained locked during this period. This geodetic analysis provides critical insights into the interseismic and postseismic coupling of the Pütürge segment within the EAF zone.