SEISMIC HAZARD ASSESSMENT AND EARTHQUAKE-INDUCED LANDSLIDE RISK ANALYSIS IN TECTONICALLY ACTIVE REGIONS

Abstract

Tectonically active areas are commonly subject to the compound threats of seismic ground shaking and landslide occurrence triggered by earthquakes, resulting in devastating human and infrastructural loss. Herein, an integrated multi-hazard appraisal strategy is offered that mingles probabilistic and seismic hazard analysis (PSHA), Newmark displacement modelling, and GIS-based landslide susceptibility mapping to assess and space-quantify risk in seismically active areas. Utilizing original data gathered from 2020 to 2024 seismic event data, digital elevation models (DEM), remote sensing imagery (Sentinel-2, PlanetScope), and regional landslide inventories the study uses a logic-tree-based PSHA in open Quake to produce site-specific ground shaking estimates. Subsequent Newmark displacement calculation is performed on the basis of critical slope acceleration and peak ground acceleration (PGA) values to provide coseismal slope deformations estimates. Concurrently, an Analytic Hierarchy Process (AHP) blended with logistic regression is applied to create a landslide susceptibility model based on terrain, geology, hydrology, and land cover data layers. The produced A multi-hazard risk map delineates 14.6% of the study area as high-risk, where slope failures will be more than 15 cm in areas of high topography, weathered lithology, and increased seismic intensity. Validation with 2020–2024 landslide inventories had an accuracy of 87.4% and an ROC-AUC of 0.91, demonstrating exceptional predictability. The results confirm that traditional single-hazard estimates grossly underestimate compound risks, particularly in populated, slope-prone regions. The research provides a strong geospatial approach to disaster risk reduction, land-use planning, and infrastructure planning in seismically active areas and contributes towards multi-hazard mitigation practice as per the Sendai Framework for Disaster Risk Reduction (2015–2030).