The CRISMA project (www.crismaproject.eu ) is a European Union funded project focusing on the simulation of multi-sectoral large scale crisis scenarios that have multi-dimensional effects on society and people. The project aims at the development of a framework to build use case specific tools which will allow decision-makers to cross-examine dynamic crisis scenario evolutions, to set action parameters of operational and strategic activities, and to visualise impacts and crisis evolvement. This will be achieved by providing a modular and open software framework to build planning and decision support systems for modelling and simulating realistic crisis scenarios and their possible consequences. CRISMA applications simulate and analyse the development of a simulated "World" in a crisis management context. A World is defined as a coherent set of data, simulation models operating on this data and the model control parameters governing the activity of these models. A snapshot of the World, or World State, consists of all data related to a specific crisis simulation experiment. This includes a set of information to control simulation models operating on the World data as well as a set of condensed, representative and quantitative information that can be used for a qualitative assessment of a world state. The user can influence a crisis evolvement by changing control parameters of the simulation models. Every modification of a World State is considered a distinct decision point and eventually produces a new World State. This leads to a decision tree. The architectural design approach uses several concepts from previous projects focusing on reference models, reference architectures and simulation-specific standards. For the CRISMA architecture, the project adopts certain common concepts that support a systematic architectural design process. In order to demonstrate and validate the design, five pilot sites are used to provide experimentation for validation and testing of a wide range of crisis management situations (coastal floods, extreme weather conditions, geophysical hazards, multi-organisational and cross-border cooperation in crisis management, planning and training for resource management). Piloting will include multi-risk and domino effects. The paper presents the business logic and key aspects of the CRISMA architecture. The work presented is work in progress, published during the design stage of the architecture. Implementation will be under way during the MODSIM 2013 conference.