Comprehensive Seismic Risk Zonation and Structural Fragility Assessment of Urban Building Typologies through Fuzzy and Probabilistic Modeling Approaches: Case Study of Muscat

Abstract

This study presents a comprehensive framework for assessing seismic vulnerability in Al-Seeb’s diverse urban building stock, which includes reinforced concrete, confined and unreinforced masonry, dual systems, and nonengineered structures. A multicriteria microzonation approach using the analytical hierarchy process (AHP) was employed to divide Al-Seeb into five seismic risk zones ( SRZs ). Structural vulnerability was modeled using a zone-specific disaster matrix with updated damage ratio (UDR) through nonlinear simulations. To capture uncertainty in damage state transitions, a fuzzy-based vulnerability membership parameter (VMP) was introduced. Additionally, three probabilistic regression models: logarithmic distribution function model (LDFM), exponential distribution function model (EDFM), and updated Gaussian distribution function model (UGFM) were compared, with UGFM demonstrating superior accuracy and robustness in modeling nonlinear behavior and undamaged states. The updated average damage index ( UADI ) method further enabled urban-scale integration of structural typology, spatial exposure, and hybrid seismic intensity (HIS) indicators. Results revealed critical seismic fragility in unreinforced masonry building (URMB), dual system building (DSB), and nonengineered building (NEB) typologies within high-risk zones, reinforcing the need for targeted retrofitting, land-use control, and resilient urban planning. This study not only addresses seismic preparedness in Al-Seeb but also contributes to global methodologies for vulnerability assessment in emerging urban centers. Aligned with United Nation’s Sustainable Development Goal (UN-SDG) 11 and Oman Vision 2040, the study offers a replicable model for enhancing resilience in moderate-seismicity regions with complex urban development patterns.