We introduce a method to specify and analyse decentralised dynamic systems; the method is based on the combination of an event-based multi-process system specification approach with a multi-facet analysis approach that considers a reference abstract model and several specific ones derived from the abstract model in order to support facet-wise analysis. The method is illustrated with the modelling and the analysis of a mobile ad-hoc network. The Event-B framework and its related tools B4free and ProB are used to conduct the experiments.