Multi-parameter soil gas geochemistry and fracture-controlled degassing along the İzmir Fault (Western Türkiye)
Applied Geochemistry, cilt.206, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 206
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.apgeochem.2026.106912
- Dergi Adı: Applied Geochemistry
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, Chemical Abstracts Core, Compendex, Environment Index, Geobase, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: CO2, Fault degassing, Radon, Soil gas geochemistry, Thoron, İzmir fault zone
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
In this study, soil gas concentrations of 222Rn (Radon), 220Rn (Thoron), and CO2 were measured along the İzmir Fault Zone in western Türkiye to investigate the relationship between gas anomalies and fault-controlled permeability. A total of 342 measurement points were systematically sampled along the two segments of the İzmir Fault (IF), spatial variations of soil gas concentrations were analyzed to identify locations that indicate anomalies. 222Rn (Radon), 220Rn (Thoron), and CO2 concentrations were determined in soil gas in the areas surrounding the fault. Quantile–quantile (Q–Q) plots were used to determine anomaly thresholds for each parameter, and concentration values exceeding these thresholds were classified as anomalies. The results reveal significant spatial variability in soil gas concentrations along the fault system. Although anomalies were detected in both segments of the İzmir Fault, multiple gas anomalies were predominantly concentrated at the westernmost end of the Balçova–Narlıdere segment. This result suggests the following regarding fault activity: The concentration of multi-gas anomalies along the Balçova–Narlıdere segment suggests active degassing processes along this part of the fault. This pattern suggests that gas distribution in the study area is not solely controlled by distance to the main fault line, but may instead reflect the heterogeneous permeability structure of the fault zone and the influence of localized fractures and preferential migration pathways. These findings demonstrate that integrated soil gas measurements provide an effective geochemical approach for identifying structurally controlled gas migration pathways and localized degassing zones in active tectonic environments.