Liquefaction susceptibility mapping of ancient city Varanasi, India
摘要
This study presents the first Analytic Hierarchy Process–Geographic Information System (AHP–GIS) integration based liquefaction susceptibility assessment framework for Varanasi, India. The Analytic Hierarchy Process (AHP) with multi-parametric geospatial modelling was used to evaluate earthquake-induced liquefaction risks through systematic integration of geo-datasets. Six crucial parameters, Peak Ground Acceleration (PGA), groundwater depth, surface elevation, shear wave velocity (Vs), soil type, and Standard Penetration Test (SPT-N) values were systematically analysed for subsurface depths 3 m, 6 m, 9 m, and 12 m. The developed AHP–GIS integration model identified soil type as the most influential factor (normalized weight: 0.3794) with high internal consistency (CR = 0.0109), demonstrating robust criterion weighting while elevation weighted to least. Spatial analysis categorized the study area into five liquefaction susceptibility classes from Very Low to Very High, revealing that 32.20% study area belongs to moderate susceptibility at 3 m depth, while 7.52% area fell into the very high-risk category, indicating significant liquefaction vulnerability in shallow subsurface zones. With increasing depth, the High susceptibility zone decreases from 27.18% at 3 m to 18.02% at 12 m, while Very Low zones expand from 12.74 to 25.89%, reflecting increasing effective overburden stress. Non-monotonic behaviour in the Very High zone (7.52–9.07%) is attributed to localised deep alluvial pockets in the southern BHU–Susuwahi corridor. This integrated AHP–GIS methodology for liquefaction assessment would provide a scientifically robust, spatially explicit decision-support framework for urban planners and policymakers.