A mature (late-cycle) seismic gap on the Eskişehir Fault, northwestern Central Anatolia, Türkiye: Fault-wide paleoseismic reconstruction and rupture potential
Tectonophysics, cilt.937, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 937
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.tecto.2026.231328
- Dergi Adı: Tectonophysics
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, Compendex, Geobase, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: 1956 Eskişehir earthquake, Eskişehir Fault, Intraplate strike-slip fault, Multi-segment rupture, Paleoseismology, Seismic gap, Time-dependent recurrence
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
The Eskişehir Fault is a NW–SE-trending right-lateral strike-slip structure that accommodates deformation between the extensional domain of western Anatolia and the comparatively rigid Central Anatolian block. Although the fault crosses the Eskişehir urban area and is associated with the damaging 1956 Eskişehir earthquake (Mw 6.5), its long-term earthquake behavior and rupture potential have remained poorly constrained. In this study, we present the first fault-wide paleoseismological reconstruction of the ∼84-km-long Eskişehir Fault by integrating new trench data from the central and eastern segments with previously published results from the western sector. Detailed geomorphic mapping and nine paleoseismological trenches, supported by 40 radiocarbon and 9 optically stimulated luminescence ages, document recurrent late Quaternary surface ruptures across all four geometric segments, with two to four events preserved per segment. Bayesian age modelling and Monte Carlo sampling were used to propagate chronological uncertainties and to evaluate recurrence behavior under a preferred quasi-periodic scenario. The resulting median recurrence estimates are ∼3.0–3.3 ka at the segment scale and ∼ 3.2 ka for the fault-wide dataset. Under this scenario, Segments 2 and 3, which underlie and immediately border the Eskişehir urban area, have not experienced characteristic surface-rupturing earthquakes for ∼2.9 ka, corresponding to normalized elapsed times of ∼88–96% of the estimated recurrence intervals. Stratigraphic relations at the Pınarbaşı trench further suggest that the 1956 earthquake produced limited near-surface deformation and did not fully reset the seismic cycle of the master fault. Considering their geometric continuity and similar kinematics, a joint rupture of Segments 2 and 3 is kinematically feasible and represents a plausible upper-bound scenario for seismic hazard assessment, potentially approaching Mw ∼6.9–7.0 according to empirical rupture-length scaling. The Eskişehir Fault should therefore be regarded as a low-slip-rate but active intraplate fault capable of infrequent, large earthquakes with significant implications for regional seismic hazard assessment.