## 2 Materials and Methods
### The Methodology  
The first information available immediately after a significant earthquake consists of the seismic event magnitude and the epicenter.. Through spatial analysis, geo-processing and visualization tools, this information together with spatial parameters such as rock and soil conditions of the affected area, distance from the epicenter and variations in the propagation of seismic waves can be processed for producing ground shaking maps overlaid with inventories of critical facilities (e.g., hospitals, schools, police and fire stations, _etc._), highways and bridges, and vulnerable structures can effectively support the response planning. [13]. Then, decision makers and responders who know where impacts of the occurred seismic event can be greatest, where structure and infrastructure have likely been damaged can act more quickly and effectively, immediately after the seismic event. Thus, predicting and mapping the seismic vulnerability of an area, assessing potential impacts of a seismic event in that area can play a crucial role in the emergency management [23]. In this research work, geospatial decision support tools that assimilate model predictions and data for mapping vulnerability to catastrophic earthquakes, scenario testing, disaster planning are investigated and developed. In particular, a simple methodology for mapping seismic vulnerability of an extensive area is investigated and related spatial resolution issues are addressed. Actually, seismic vulnerability analysis is performed at regional scale while commonly it is at local scale. The resolution issue is addressed by identifying potential earthquake sources in the interest regional area. Potential earthquake sources can be selected within the deployment area of a seismic monitoring network or by parametric catalogue of disastrous earthquakes in regional area (the catalogue used for the  
Figure 1: Study area and geographic location of Irpinia Seismic Network (ISNet). study case was retrieved from INGV--Italian National Institute of Geophysics and Volcanology, [[http://www.ingv.it/eng](http://www.ingv.it/eng)]([http://www.ingv.it/eng](http://www.ingv.it/eng))). The following steps of the investigated procedure are basically:  
1. estimate the earthquake ground motion attenuation with the distance from the seismic epicenter;
2. evaluate local site effects of soil amplification;
3. estimate the damages to the facilities inventories. Local geologic deposits are well known for their capabilities to modify the characteristics of seismic motions and influence the amount of damage to buildings [24]. Then, the surface ground motion of earthquakes is heavily influenced by the subsurface ground conditions, especially in areas covered by thick sediments. In order to evaluate the distribution of earthquake motion across a wide area, it is necessary to evaluate the difference in the subsurface amplification, site by site. A geology map has been used to classify the study area at regional scale (as depicted in Figure 1) on the basis of different litho-technical types. Slope and hillshade maps, topographic profiles and curvature maps have been generated by using a Digital Terrain Model (DTM) of the study area. Thus, specific indicators of local site conditions have been extracted by these spatial layers such as the distribution of unconsolidated, youngest sedimentary covers that can often be correlated to areas showing less than 10 \({}^{\circ}\)slope gradient and no curvature. DTM and topographic profiles of the interest area allow identifying depressions covered by recently formed sediments, which are related to relatively higher groundwater surface. These areas have frequently shown the highest damage intensities in case of seismic events. In order to quantify the effects of local soil conditions on the earthquake ground motion amplification, empirical multiplication factors are generally used.