Design of a virtual test bed for the Italian territory: Proof of concept for multi-hazard scenarios effects in the context of a national resilience assessment

This study presents a proof‑of‑concept virtual test bed—RETURNLAND—designed to model multi‑hazard scenarios and support national resilience assessment across Italy. Developed under the Italian National Recovery and Resilience Plan, it integrates geomorphological, geological, marine and urban elements to simulate cascading disaster risks, including landslide‑generated tsunamis, volcanic ash fall and pyroclastic density currents, coastal flooding, subsidence and climate‑driven sinkhole formation. Built by mosaicking real territorial portions into a synthetic but realistic digital elevation model, RETURNLAND provides a scalable environment for testing analytical tools, machine‑learning approaches and digital‑twin concepts applicable to diverse Italian physiographic settings. 

The study highlights the need for integrated, forward‑looking risk assessment tools and recommends the use of virtual test beds to evaluate multi‑hazard interactions, inform preparedness and guide resilient territorial planning. It emphasises the value of combining numerical modelling, geomorphological analysis and machine‑learning techniques to anticipate future impacts, particularly under climate‑change conditions. The authors encourage the adoption of RETURNLAND‑type environments to stress‑test infrastructure, assess vulnerability in both terrestrial and marine domains, and support decision‑makers in designing mitigation strategies that account for cascading effects, long‑term coastal change and the increasing complexity of natural hazard dynamics.