Development of a Natech Social Vulnerability Index: A Comprehensive Multi-Hazard Risk Assessment for a Case Study in Colombia

Natech refers to complex scenarios where secondary technological accidents are triggered by natural disasters, having the potential to cause severe societal loss, especially in developing countries such as Colombia, potentially due to its vulnerable social system (Ran, MacGillivray, Gong, & Hales, 2020) (Porto & Freitas, 2003). However, one major identified research gap is the lack of a specific approach to assess the Natech social vulnerabilities. A popular vulnerability assessment tool: social vulnerability index, widely used for natural and industrial hazards, shows promising usability for Natech vulnerability assessment. The current study has proposed a novel methodology to assess Natech social vulnerability by establishing a Natech social vulnerability index based on identification of the Natech scenarios and investigation of multi-hazard intercorrelations. To validate the introduced methodology, the author utilized rainfall-induced, landslide-triggered chemical Natech incidents in Colombia as a representative case. The study embarked on identifying distinct hazards present in varying Natech situations to determine which social elements amplify vulnerability. Subsequently, composite indicators, or social vulnerability indices, were formulated to quantitatively amalgamate these pinpointed social elements. These were mapped within diverse vulnerability conceptual paradigms and then refined and scrutinized using Structural Equation Modelling (SEM). The outcomes, portrayed via a Geological Information System (GIS), predominantly resonate with preceding studies. Nonetheless, certain fit index values signal potential ambiguities in model alignment. The paper concludes into the inherent challenges and constraints of the devised methodology. Grounded on these analyses, policy recommendations tailored for the Colombian government’s vulnerability assessment have been proposed. These include advisories on refining the national census, databanks, and Natech reports. Additionally, pivotal research directions have been highlighted to address and mitigate the acknowledged research shortfalls in impending studies. In summary, this research, encompassing its innovative methodology, findings, and advisories, serves as a pivotal reference for succeeding investigations on social vulnerability assessments related to Natech and other multi-hazard events.