How did two large (M>6.5) earthquakes affect creep rates on the Pütürge segment of the East Anatolian Fault?

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

Submitted August 30, 2026, SCEC Contribution #15606, 2026 SCEC Annual Meeting Poster #TBD

The Pütürge segment of the East Anatolian Fault (EAF) in eastern Turkey is a known creeping segment, where two large-magnitude (M>6.5) earthquakes (the 2020 M6.7 Elazig and the 2023 M7.7 Pazarcık earthquakes) have failed to rupture the surface (Konca et al., 2021; Cakir et al., 2023; Barbot et al., 2023). Ongoing surface deformation in the area suggests the fault may still be experiencing triggered creep following the latter event. To better understand potential ongoing hazards of large-magnitude earthquakes on creeping faults, the Pütürge segment offers an opportunity to investigate changes in creep rates from inter- to post-seismic, how long the creep rate may be elevated, and whether there is an ongoing seismic hazard on the creeping segment.

We use InSAR data from satellite Sentinel-1, along with the MintPy software, to build multiple time series spanning the interval 2014 to 2026, using interferograms processed by the JPL ARIA project, and supplement these with interferogram stacks processed using the ISCE2 software. Shallow creep rates will be characterized over three time periods, and the post-seismic rates compared to assess whether post-seismic velocities for either tectonic event have returned to pre-2020 rates.

Observations suggest changes in creep rates, including background (non-seismic) and seismically triggered variations from the 2020 M6.7 Elazig and 2023 M7.7 Pazarcık earthquakes. For the period 2014-2020, the shallow creep rate is not constant but changes behavior around 2018, with a rate increase observed one to two years before the Elazig earthquake. This change does not appear seasonal, is limited to a specific fault area, and we are still analyzing its implications. From 2020 to 2023, a decreasing post-seismic deformation rate is observed. For the post-2023 Pazarcık earthquake creep rates (2023-2026), a post-seismic decrease is localized to the southern Pütürge segment, warranting closer scrutiny. Characterizing changes in creep rates can inform local seismic hazard assessments and provide insight into creep-rate tectonic risks, including the magnitude, period, and spatial extent of creep-rate changes, as well as provide context for local infrastructure on how creeping fault segments in California may respond after a large earthquake.

Key Words
creep rates, InSAR, East Anatolian Fault

Citation
Hofstetter, C. N., Özarpacı, S., & Funning, G. J. (2026, 08). How did two large (M>6.5) earthquakes affect creep rates on the Pütürge segment of the East Anatolian Fault?. Poster Presentation at 2026 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy