A closer look at interseismic creep and postseismic deformation on the Pütürge segment of the East Anatolian Fault

Celeste N. Hofstetter, Seda Özarpacı, & Gareth J. Funning

Submitted September 7, 2025, SCEC Contribution #14889, 2025 SCEC Annual Meeting Poster #TBD

The East Anatolian Fault (EAF) in eastern Turkey exhibits heterogeneous frictional behavior, with both stick-slip and creeping fault segments. It has also experienced several large (M>6.5) earthquake ruptures in recent years, including the 2020 M6.7 Elazig and 2023 M7.7 Pazarcık earthquakes. A portion of the Pütürge segment of the EAF, bracketed by the 2020 and 2023 events, failed to rupture in either earthquake, raising the question of why did it not. To investigate this, we use InSAR data, analyzing over 2,000 ARIA Standard Product and ISCE2 TOPS Stack-generated interferograms, to estimate surface deformation along the Pütürge segment from 2014 to 2024. Our goal is to characterize the heterogeneous slip behavior along the segment and its possible role in the arrest of the 2023 Pazarcık earthquake rupture.

We focus on InSAR data from two tracks, ascending track 116 and descending track 123, and generate velocity maps, profiles, and differential time series to investigate the pattern and time dependence of slip along the Pütürge segment.

We find the surface displacement varies spatially and temporally along the fault. Interseismic (pre-2020) creep rates of up to ~6 mm/yr are observed nearest Lake Hazar in the northeast, with rates decreasing to effectively zero at the segment’s southwest end. We find more rapid displacements during the two post-seismic periods. Up to ~12 cm of total displacement was observed on the Pütürge segment after each tectonic event (2020 M6.7 Elazig and 2023 M7.7 Pazarcık earthquakes), with the highest displacement occurring on the EAF near the rupture terminations. Post-seismic triggered creep is also observed to extend into interseismically locked segments, suggesting creep frictional properties may extend further to the SW on the Pütürge segment than previously known.

Key Words
creep, InSAR, East Anatolian Fault

Citation
Hofstetter, C. N., Özarpacı, S., & Funning, G. J. (2025, 09). A closer look at interseismic creep and postseismic deformation on the Pütürge segment of the East Anatolian Fault. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy