Abstract. The recent advances in geo-informatics have been opening new opportunities in earthquake early warning and emergency management issues. In the last years, the geo-scientific community has recognized the added value of a geo-analytic approach in complex decision making processes for critical situations due to disastrous natural events such as earthquakes. In fact, recently, GIS-based solutions are investigated in several research projects such as SIT_MEW Project, aimed at the development of volcanic and seismic early warning systems (EWSs). In this project context, an innovative open source GIS system has been investigated and developed as integrated component of the seismic EWS. Its architecture consists in a geospatial database system, a local GIS application for analyzing and modelling the seismic event and its impacts and supporting post-event emergency management, a WEB-GIS module for sharing the geo-information among the public and private stakeholders and emergency managers involved in disaster impact assessment and response management.