Interacting normal and strike-slip fault systems in Western Anatolia: InSAR-constrained rupture and aftershock migration of the 2025 Sındırgı earthquake, Türkiye
Journal of Asian Earth Sciences, cilt.309, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 309
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.jseaes.2026.107171
- Dergi Adı: Journal of Asian Earth Sciences
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Geobase, INSPEC, Zoological Record
- Anahtar Kelimeler: InSAR, Mixed-mode rupture, Simav fault zone, Transtension, Western Anatolia
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
Intersecting normal and strike-slip fault systems in Western Anatolia complicate strain redistribution. The 10 August 2025 Sındırgı earthquake (Mw 6.1) on the Simav Fault Zone provides a critical opportunity to examine this interaction. No clear primary surface rupture was reported, consistent with a buried (blind) normal-fault source. This study constrains rupture geometry and fault interaction using Sentinel-1 InSAR observations and Coulomb stress modeling. Sentinel-1 InSAR data resolve an E-W elongated deformation footprint (∼22 × 12 km) with peak Line-of-Sight (LOS) displacements of ∼15 cm. Bayesian inversion of this displacement field indicates that the mainshock ruptured a blind, NE-dipping normal fault (L ≈ 9.45 km, dip ≈ 41°) centered at ∼13 km depth, with the deformation hinge line offset by ∼1‒2 km into the footwall relative to the mapped trace. Although the mainshock was a normal faulting event, the aftershock sequence exhibits an increasing strike-slip contribution. Static Coulomb stress changes (ΔCFS) reveal positive loading on nearby right lateral receiver faults, supporting stress-mediated mixed-mode activation. Furthermore, the spatiotemporal evolution of aftershocks suggests progressive eastward redistribution of activity toward the Simav segment. These combined observations are consistent with a transtensional transfer setting rather than a simple normal fault rupture. The inferred source parameters are interpreted within the context of associated uncertainties, particularly given the one-day acquisition interval and potential atmospheric residuals. Consequently, hazard assessments should explicitly consider complex displacement transfers and the potential for triggering adjacent strike-slip structures.