Akademik Veri Yönetim Sistemi
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, cilt.27, sa.1, 2026 (SCI-Expanded, Scopus)
This study presents a soil gas geochemical survey in the K & imath;rcao & gbreve;lu and Reyhanl & imath; regions of Hatay Province, southeastern T & uuml;rkiye, following the 2023 Kahramanmara & scedil; earthquake doublet. The aim was to identify concealed faults and assess seismic hazard through analysis of soil CO2 flux, CO(2 )and( 222)Rn concentrations, and carbon and helium isotopic compositions. A total of 98 sites were surveyed, and graphical statistical methods were used to establish geochemical anomaly thresholds. In K & imath;rcao & gbreve;lu, two prominent gas anomaly zones were delineated with dominant NW-SE and NE-SW trends, likely representing buried faults linked to the Yesemek Segment, including one beneath the Reyhanl & imath; Dam. In Reyhanl & imath;, an east-west gas anomaly suggests a possible westward extension of the Reyhanl & imath; Fault. These findings refine the region's structural framework and highlight seismic risks from buried faults. Isotopic analyses show CO(2 )derives from biogenic and deep crustal reservoirs, with He-4/Ne-20 and 3He/4He ratios confirming up to 7.1% crustal helium and <1% mantle helium. Heavier delta C-13 values and elevated crustal helium in K & imath;rcao & gbreve;lu support deep gas migration along fault zones. Natural CO2 emissions are estimated at 66 t/d in K & imath;rcao & gbreve;lu and 60 t/d in Reyhanl & imath;. Regionally, emissions from the Amik Basin (similar to 15,586 t/d) comprise similar to 1.5% of T & uuml;rkiye's daily anthropogenic CO2. The overlap between gas anomalies and surface ruptures and liquefaction zones from the 2023 earthquakes confirms the effectiveness of soil gas surveys for buried fault detection. These results highlight the utility of soil gas geochemistry as a non-invasive tool for fault detection and seismic hazard assessment. Plain Language Summary In this study, scientists examined soil gases in the K & imath;rcao & gbreve;lu and Reyhanl & imath; regions of Hatay Province, southeastern T & uuml;rkiye, after the 2023 earthquakes. The goal was to better understand hidden faults underground that could cause future earthquakes. CO2, and Rn gases were measured at 98 sites using specialized equipment. Two areas showed unusual gas patterns. In K & imath;rcao & gbreve;lu, gas was leaking along two narrow subsurface paths, likely linked to the Yesemek Segment fault. One of these paths passes beneath the Reyhanl & imath; Dam. In Reyhanl & imath;, the gas distribution indicated that the local fault might extend farther west than previously believed. The gases came from surface biological activity and deep underground sources. The presence of deep gases, especially in K & imath;rcao & gbreve;lu, suggests that these faults may allow gases to rise from the Earth's crust. This helps in assessing earthquake risk. The CO2, emissions from both areas are significant and contribute to T & uuml;rkiye's natural greenhouse gases. Notably, gas patterns corresponded with areas damaged by the 2023 quakes, including surface ruptures and soil liquefaction. This confirms that soil gas studies can help detect buried faults. Researchers suggest that soil gas monitoring can improve earthquake hazard assessments in densely populated regions and places with critical infrastructure.