## 1 Introduction  
In the past few years, the human population has experienced a series of natural disasters such as hurricanes, tsunamis, earthquakes (see, for example Aquila (IT) earthquake in 2009, Tohoku (Japan) tsunami in 2011, Turkey earthquake in 2011, _etc._), floods, fires, landslides among others, that have in many cases overwhelmed the responding and recovering capacities. With modern geospatial technologies such as satellite imaging and geographical services (e.g., Google Earth(r)) it has been possible to see through Internet the magnitude of these natural disasters and how breakdown can often be complete and pervasive in an era of technological and information abundance [1]. Indeed, these disastrous events, have also drawn the attention of all types of people--from the scientific community and public decision makers, to stakeholders and common citizens--to the importance of geographical information and technology in all aspects of disaster management (DM), _i.e._ from planning for disastrous events that may have lead, through response and recovery, to the mitigation of these events, but also to the problems that can arise in the immediate aftermath of a disastrous event if adequate geospatial information are not available for damage assessment and response planning. Just as examples, Earth-observation satellites might not pass over the affected area for several days and the images might be obscured by clouds and/or smoke in case of fires. Further, the lack of power, internet connections or computer hardware and software might prevent the use of digital data, tools and services relevant to emergency management or other impediments to their effective utilization, such as the lack of knowledge about: what data and tools exist and where; restrictions on their use; lack of training on the part of users, and so on [2]. Modern approaches to emergency management and response involve efforts to reduce the vulnerability to hazards; to diminish the impact of disasters; and to prepare for, respond to, and recover from those that occur [1]. Geospatial data and tools have the potential to contribute to all these emergency tasks [3]. Decision makers and responders, who know where disaster impacts are greatest, where critical assets are located or where infrastructure has likely been damaged, will be able to act more quickly and effectively, especially immediately after the event [4]. It is possible to imagine the chaos if first responders are entirely unfamiliar with an area and have none of the geospatial information--maps, GPS coordinates, images--essential to effective emergency management. Currently, a crucial contribution to the response planning can also derive from Volunteered Geographical Information (VGI) created by amateur citizens [5], who, familiar with the affected area, report the status of this area and aftermath disaster event through its spatial coordinates and contribute information by using mobile devices (such as smartphones, tablets or cameras enabled with GPS) [6] or _ad hoc_ Web-GIS services [7]. VGI is timely and at local scale, properties that are needed in the disaster early warning and post event emergency management. The added value of VGI in disaster emergency management situations, the enabling technologies, collectively termed Web 2.0, and _ad hoc_ geospatial tools to develop and diffuse, collect, synthesize, verify, and redistribute this information have been extensively discussed and investigated by the scientific and technological communities (see, for example [2, 8, 9, 10, 11] among others). Over the past few decades, specific needs related to geospatial technology, data infrastructure and tools for supporting disaster early warning and emergency management tasks, especially for disastrous earthquake events, have only been addressed in a few cases [12]. Our focus is on earthquake earlywarning systems (EWS), their architectures and functionalities.