Modelling Cascading Multi-Hazards: From Risk Theory to Graph Simulation

Abstract

Natural hazards rarely occur in isolation. They unfold as complex cascades of interconnected phenomena, where interactions alter impacts beyond what single-hazard assessments can reveal. This talk explores emerging approaches to multi-hazard risk theory, from the epistemic tradeoffs of the bias–variance dilemma to the challenges of modeling in non-ergodic systems.

Dr. Alexandre Dunant will introduce network-based simulations that explicitly encode relationships among hazards, vulnerabilities, and exposures, generating probabilistic multi-hazard scenarios that better capture interdependencies and feedbacks. By drawing on insights from complexity science and graph theory, these models offer a bridge between theoretical understanding and practical tools for decision-making under uncertainty.

The discussion will highlight both the promise and the limits of modeling. Ultimately, representing connections can guide preparedness, illuminate systemic vulnerabilities, and inform adaptive interventions in multi-hazard-prone regions.

Biography

Dr. Alexandre Dunant is a Senior Researcher at the Center for Climate Change and Transformation at Eurac Research in Bolzano, Italy. He earned a Master’s in Earth Sciences from Vrije Universiteit Amsterdam and a Bachelor’s in Biology from Rennes University, France. He began his career as an Exploration Geoscientist at Shell, focusing on offshore and onshore projects in the UK, Netherlands, and Brazil. He later pursued advanced studies in deep geothermal systems at Université de Neuchâtel and completed a PhD in Disaster Risk and Resilience at the University of Canterbury, New Zealand, where his research centred on quantifying risks in complex natural hazard systems. From 2018 to 2021, he served as a Research Risk Scientist at GNS Science in New Zealand, developing probabilistic multi-hazard models. As a Postdoctoral Research Associate at Durham University (2021–2024), he contributed to the Sajag-Nepal project, advancing national-scale preparedness for catastrophic multi-hazards. Alexandre’s work bridges multi-risk theory, network and hypergraph simulations, and practical applications in disaster risk reduction, with a focus on regions like Italy, Nepal and New Zealand.