Lifelines are especially vulnerable to seismic events due to their spatial distribution. Seismic shocks at individual locations may affect the functionality of the whole system, impairing resilience of the hit area and worsening post-disaster response. Performance assessment for distribution networks is not yet a well established topic in earthquake engineering and presents several peculiar issues due to the interdependencies existing between components, and the performance indicators which refer more to serviceability rather than physical damage as it happens for buildings.

In the paper, referring to the 6^th April 2009 L'Aquila earthquake, a description of the gas distribution system of L'Aquila province is presented. Subsequently, the assessment of the damage occurred to the system and the residual functionality is analyzed on the basis of post-event repair reports from the network operator, Enel Rete Gas. Finally a discussion of interdependencies between components and subcomponents of the system, in terms of fault tree analysis, is also given as a step to indentify the most critical elements to consider in seismic risk assessment of gas distribution network.