Earthquake risk assessment of critical gas infrastructure is essential for improving environmental risk management, emergency preparedness, and infrastructure resilience in seismically active regions. Fourteen environmental and spatial conditioning factors, including distances to gas pipelines, pressure reduction stations, faults, major roads, and rivers; historical earthquake events; slope; aspect; elevation; annual rainfall; soil type; lithology; land use; and climate (Aridity Index), were compiled, standardized, and transformed using fuzzy membership functions. The standardized fuzzy layers were integrated using the Fuzzy Gamma operator to generate earthquake risk scenarios. A sensitivity analysis was conducted using three gamma values (γ = 0.7, 0.8, and 0.9) to evaluate the influence of the gamma parameter and determine the optimal configuration. The results indicated that γ = 0.8 provided the most reliable performance by achieving the best spatial differentiation of risk classes, with an area under the receiver operating characteristic curve (AUC) of 0.817. The final risk map showed that 12.65% and 26.58% were classified as Very High and High-risk zones, respectively, accounting for 39.23% of study area. Furthermore, the infrastructure exposure analysis demonstrated that 71.73% of main gas pipeline length and 83.33% of pressure reduction stations were located within High- and Very High-risk zones, highlighting the concentration of critical gas assets in earthquake-prone areas. The developed framework provides a risk-informed, decision-support approach for prioritizing infrastructure inspections, planning seismic mitigation and retrofitting measures, improving emergency response strategies, and enhancing the resilience of gas infrastructure systems. This study contributes to the sustainable, evidence-based management of critical energy infrastructure in earthquake-prone regions.