A GIS-based multi-criteria approach for identifying areas vulnerable to subsidence in the world's largest ongoing urban socio-environmental mining disaster

Abstract

This study proposes a GIS-based multi-criteria approach to identify areas vulnerable to subsidence in the world's largest ongoing urban socio-environmental disaster, caused by salt-gem urban mining in Maceió, Alagoas State, Brazil. The analysis revealed critical areas concentrated in regions with salt-gem mines and soil composed of sedimentary rocks near water bodies, where the local population faces significant socio-economic challenges. In addition to addressing environmental vulnerabilities, the developed methodology considers social and economic risks, aiming for integrated actions between the population and the environment. The FITradeoff multi-criteria method used in the geospatial model showed benefits, including a significant reduction in the number of inconsistencies required for geospatial decision-making, ensuring efficiency in the development of prevention and mitigation strategies. The Spatial Inference model showed a high level of accuracy of 88.89 % in classifying the vulnerability of Maceió’s neighborhoods to subsidence, although it faced challenges when assessing neighborhoods with distinctive characteristics. The proposed preference-driven multi-criteria model incorporates decision-maker preferences, opinions, and knowledge of this disaster. Under specific conditions, this model can offer tailored solutions that align with stakeholders’ objectives. The results provide valuable insights for the development of public policies and risk management strategies in affected areas and areas vulnerable to subsidence due to urban mining in Maceió, and may be applicable to other regions of Brazil and the world facing similar challenges.