Natural gas networks are spatially distributed systems that play a crucial role in the well-being and safety of communities. Most of the works in the current literature analyse natural gas systems only in topological terms. However, the low tolerance on amount and pressure of gas fed to end-users for maintaining serviceability generates the need for a capacitive analysis. The latter includes connectivity and involves computation of the system's operational state, in terms of pipe flows and node pressures. The paper presents a comprehensive methodology for the seismic risk assessment of gas transmission and distribution networks. The seismic hazard, the vulnerability assessment and the evaluation of the system's performance are addressed with a simulation-based approach, accounting for the relevant uncertainties. The use of the capacitive analysis in this scope represents the most important feature of this work: a complete steady-state flow formulation is used, encompassing multiple pressure levels, the pressure-driven mode and the correction for pipe elevation change. The presented methodology has been implemented into an open-source software, OOFIMS, and applied to a realistic benchmark network composed of 135 nodes and 170 edges, thus resulting to be usable by emergency managers and stakeholders engaged in increasing the seismic resilience of communities.

天然气网络是空间分布的系统，对社区的福祉和安全起着至关重要的作用。当前文献中的大多数作品仅以拓​​扑学的方式分析天然气系统。但是，为保持可维护性而输送给最终用户的气体量和压力的容忍度较低，因此需要进行电容分析。后者包括连通性，并涉及根据管道流量和节点压力计算系统的运行状态。本文提出了一种用于天然气输配管网地震风险评估的综合方法。地震危险性，脆弱性评估和系统性能评估均采用基于仿真的方法解决，并考虑了相关的不确定性。在此范围内使用电容分析是这项工作的最重要特征：使用了完整的稳态流量公式，其中包括多个压力水平，压力驱动模式和管道高程变化的校正。所提出的方法已实施到开放源代码软件OOFIMS中，并应用于由135个节点和170个边组成的现实基准网络，因此，应急管理人员和参与社区抗震能力增强的利益相关者都可以使用。