Stay-or-relocate model (STORM): An agent-based population displacement simulator applied to a multi-phase volcanic eruption scenario

This study presents the Stay‑or‑Relocate Model (STORM), an agent‑based population displacement simulator designed to support disaster risk reduction by modelling how households decide whether to remain, relocate, or return home during a multi‑phase volcanic eruption. Applied to the Taranaki Region of Aotearoa‑New Zealand, the model integrates fine‑scale hazard, infrastructure, demographic and behavioural data to simulate displacement dynamics across eruptive phases, including ashfall, lahars, service outages, school closures and community disruption. It addresses a critical gap in existing tools by capturing evolving household circumstances over time and by incorporating an empirical relocation module that estimates accommodation choices, duration of displacement and return patterns. 

The study recommends strengthening decision‑support capabilities for emergency managers by adopting models that account for heterogeneous household characteristics, evolving hazard conditions and interdependent infrastructure failures. The authors suggest that future applications of STORM could enhance preparedness planning, guide investment in resilient infrastructure, and support more equitable recovery strategies by identifying vulnerable populations and critical decision points throughout prolonged or multi‑hazard events.