Towards an integrated interdisciplinary approach for large-scale modelling, simulation and management of natural disasters. A virtual case study urban area

The unacceptable consequences of recent natural hazard-related disasters such as earthquakes, landslides, floods, and intense rainfall have further highlighted the urgent need for a coordinated effort among researchers, practitioners, and governments to develop and implement effective disaster risk reduction policies in many countries worldwide. In Italy, several research studies in the last decades have been focusing on the analysis of natural hazards (single, chained or multiple) and the evaluation of the associated risks to the built environments, including the quantitative estimation of socio-economic impacts. Yet, a robust integrated approach capable of quantifying the interdependent impacts of multiple and multi- hazard scenarios and support, as a high-level decision-making operational “dashboard”, the development of multi-risk reduction and resilience enhancement strategies at a national level, is still missing and urgently needed. The primary challenges of such a topic involve the need for: (i) a multi-scale evaluation of both different hazards (e.g., from large-scale simulations to more detailed site-specific effects and in-situ observations) and exposure-vulnerability models (e.g., from territorial scale up to single structures/infrastructure and advanced Digital Twin model); (ii) properly considering inter- and intra-dependencies among infrastructural components (building stock, utility network, road network); (iii) accounting for uncertainties related to data availability and limited knowledge; (iv) huge computational resources to manage the required massive amounts of data. In this context, as a part of a wider PNRR (National Recovery and Resilience Plan) – National Research Centre on High Performance Computing, Big Data and Quantum Computing (CN1) research project, this paper presents and discusses the ongoing activities carried out by an large interdisciplinary team of engineers, geologists, and geophysicists on large-scale modelling, simulation, evaluation and management strategies for natural disasters. Particularly, a major effort is devoted to the development of an integrated framework for scenario-based multi-risk assessment of urban areas, following an input-output data supply chain or “domino-like” sequential approach, primarily triggered by earthquake events. The workflow involves the following steps: (i) earthquake rupture simulations and seismic wave propagation; (ii) site-specific amplification analysis due to stratigraphic and topographic conditions; (iii) assessment of earthquake-induced natural events (such as earthquake-induced landslides); multi-scale and multi-refinement level risk assessment of the urban area considering different interconnected layers (building stock, water distribution system, road network); (iv) evaluation of risk metrics – Key Performance Indicators (KPIs) of primary interest for end-user and stakeholders, e.g., deaths, economic losses, downtime. The paper introduces the proposed methodology and discusses in more detail the development of a Proof- of-Concept (PoC) demonstrator, consisting of a Virtual Test Bed (VTB) ecosystem, based on an innovative approach where a virtual, i.e., realistic but not real, case study urban area, located in a multiple-hazard-prone zone, is populated by buildings of different use and material, and lifelines/infrastructures. The unique opportunity of implementing such an integrated digital twin-based framework within an HPC environment can represent a powerful decision-making tool supporting the management and planning of disaster risk reduction strategies and, ultimately, enhancing the resilience of our communities.