## 1 Introduction
The main components of an earthquake EWS are a central unit (operating centre) and a seismic sensor network connected by a high-speed communication network. The kernel of the operating center is generally a data mining and decision support system (DSS) that processes the earthquake magnitude and epicenter information and enables the operators to make decisions and to disseminate EW [13]. The generated alarm is used to evacuate buildings, shut-down critical systems (e.g., nuclear and chemical reactors), put vulnerable machines and industrial robots into a safe position, stop high-speed trains, activate structural control systems and so on [14]. Immediately following an earthquake, the operating center also has to support emergency response and rescue operations, but only using earthquake magnitude and epicenter information might not be sufficient. In fact, the damage pattern is not a simple function of these two parameters alone, and more detailed information must be provided to properly assess the situation and adequately plan and coordinate emergency response. Although an earthquake has one magnitude and one epicenter, it produces a range of ground shaking levels at sites throughout the region depending on distance from the source, rock and soil conditions at sites and variations in the propagation of seismic waves due to complexities in the structure of the Earth's crust. Ground shaking maps can thus be generated by using specific geospatial datasets and advanced spatial analysis tools [15]. They can also be used for emergency response tasks and for public information through the media. For example, maps of shaking intensity can be combined with databases of inventories of buildings and lifelines to rapidly produce maps of estimated damage. Therefore, geospatial data and tools are needed to support quick analysis of the situation during and immediately following an earthquake and facilitate critical decision making processes. Recently, a number of specific applications for rapidly assessing the extent of shaking and potential damage following an earthquake have been developed. USGS-ShakeMaps [16] and ElamS [17] are two significant applications among others. ShakeMap application rapidly and automatically generates shaking and intensity maps, combining instrumental measurements of shaking with information about local geology and earthquake location and magnitude. This application displays its results through a variety of map formats. These maps can thus become tools for earthquake early warning and emergency response systems. Elams (Earthquake Alarm System) application, developed by the University of California Berkeley, provides the prediction of the distribution of peak ground shaking across the region affected by an earthquake before the beginning of significant ground motion. A map of predicted ground shaking is thus generated, also using datasets of past and probable future earthquakes. More specifically, Elams is a suite of algorithms designed to: (1) rapidly detect the initiation of an earthquake; (2) determine the size (magnitude) and location of the event; (3) predict the peak ground motion expected in the region around the event; and (4) issue a warning to people in locations that may expect significant ground motion. The algorithms use data from regional broadband seismic networks. Due to the complexity of earthquake phenomena, the spatiotemporal nature of the seismic data and the very large amount of data collected by seismic monitoring networks, up-to-date earthquake EWS have been evolving towards more complex and integrated architectures [18]. In particular, these architectures are composed of integrated _so-called_ seismic data management and mining systems (SDMMSs) [18] and Geographical Information Systems (GISs).