The 6 February 2023 M7.8 & M7.6 earthquake ruptures mapped with InSAR

Data Supporting Text

We used C-band SAR (Sentinel-1) data in order to extract information about the ground displacements that occurred due to the Mw=7.8 earthquake and Mw=7.6 earthquake in southeast Turkey (Türkiye). We retrieved the satellite data from the Alaska Satellite facility and from the Copernicus Hub of ESA. We used differential SAR (DInSAR) and the sub-pixel correlation methods to retrieve the surface motions in LOS direction and in azimuth (along satellite track) direction. We processed the SAR images using the (ISCE) v2 software and we applied pixel offset tracking through the cross correlation of the amplitude of the primary (before the earthquake) and the secondary (after the earthquake) SLC images. The pixel offset method gave us the capability to map the surface rupture extent of the strike-slip fault segments along the East Anatolian Fault Zone (EAFZ) and the Sürgü fault (SF). Also, we identified the splay fault known as Nurdağı-Pazarcık fault (NPF; Melgar et al. 2023) where the rupture process began and a second splay fault in the area of Adiyaman near the main trace of EAFZ. We mapped the total rupture length of the EAFZ which is ~ 400 km. We suggest that the maximum displacement was ~ 7 m in line of sight (LOS) direction (central area of EAFZ and SF). Also, the maximum displacement of the NPF was found ~ 1 m. It is necessary to clarify that the total displacement field occurred by the combined motion of the two mainshocks, as well as, possibly by some large-magnitude aftershocks.

Acknowledgments

This research was supported by the Hellenic Foundation for Research and Innovation (HFRI) under the 3rd Call for HFRI PhD Fellowships (Fellowship Number: 05176).

References

Melgar, D., Taymaz, T., Ganas, A., Crowell, B., Öcalan, T., Kahraman, M., Tsironi, V., Yolsal-Çevikbilen, S., Valkaniotis, S., Irmak, T. S., Eken, T., Erman, C., Özkan, B., Dogan, A. H., & Altuntaş, C. 2023. Sub- and super-shear ruptures during the 2023 Mw 7.8 and Mw 7.6 earthquake doublet in SE Türkiye. Seismica, 2(3). https://doi.org/10.26443/seismica.v2i3.387