# Strong Ground Motion Sensor Network for Civil Protection Rapid Decision Support Systems
## 5 Discussion and Conclusions  
The response spectra from a strong motion sensor after large events provide useful information for the civil protection agencies related to the ground acceleration values which can be compared to the seismic design of buildings curves and assess the potential damage. Having a considerable number of sensors deployed on the different geological formations and city areas with variable vulnerability, makes possible the thorough yet direct examination of the broad urban environment. With the use of several event recordings for a specific station, it is feasible to identify areas with amplified site effects. This outcome can be used both for proactive decisions as well as prompt actions for emergency response and for long-term prevention measures to mitigate earthquake risk, e.g., increase the building stock resilience. In Chania city, the stations located in loose Quaternary deposits show that there is an increased trend in the spectral acceleration values for the most of studied cases compared to  
Figure 6: For the EQ.7 Samos strong event, Northeast of Chania, ground motion parameter spatial distribution results obtained from Ordinary Co-Kriging: (**a**) Peak Ground Acceleration in cm/s\({}^{2}\); (**b**) Peak Ground Velocity in cm/s; (**c**) Peak Ground Displacement in mm and (**d**) Arias Intensity in cm/s. PERI-station was offline. the sensors that are in the stiffer Neogene limestone. The large variation in the acceleration values is due to the considerably different thickness and material stiffness in the Quaternary basin. The available data show that there are site effects from continuous lateral refractions and reflections of trapped waves inside the basin as well as seismic wave reflections on a vertical surface such a suspected fault [12]. An extra focus should be given to these locations as it is very possible to experience more structural damage from a future strong earthquake. Examining only the PGA spatial distribution maps after a strong ground shaking is not always the best option as the results visualize partial aspects of the total image especially when there are near-fault directivity effects [32]. The maximum acceleration maps between an intermediate depth 6.1 magnitude earthquake with 70-km epicentral distance (EQ.3) and a shallow event with local magnitude 4.5 (EQ.4) and epicenter closer to Chania by 30 km demonstrate similar results. The minimum and maximum PGA values are on the same range while the rest ground intensity map measures for EQ.4 have significant lower values than those for EQ.3. The strong ground motion sensor networks effectively and promptly provide comprehensive information for a rapid DSS. First, it produces near real time ground intensity parameter spatial distribution maps which provide decision-makers with an image of the potential structural damage. Secondly, by building a database with a series of events, the developed methodology could be incorporated within a rapid DSS for civil protection to simulate or assess long-term seismic-risk reduction options and actions (e.g., land-use, land-use planning, public infrastructure, building codes etc.) as well as short-term ones (e.g., early warning, evacuation plans, emergency actions coordination). It is operational in different spatial and temporal scales and resolutions, visualizes the strong seismic motion effects, and conveys earthquake hazard risk information in a graphical, user-friendly, and intuitive way to support civil protection decision-makers. Conceptualization, I.P., G.C., and F.V. ; methodology, I.P. and F.V. ; software, G.C. ; validation, G.C., I.P., and F.V. ; formal analysis, G.C. ; data curation, G.C. ; writing--original draft preparation, G.C. and J.P.M. ; writing--review and editing, J.P.M. and F.V. ; visualization, G.C., M.K., and J.P.M. ; supervision, F.V. and I.P. All authors have read and agreed to the published version of the manuscript. This research was co-funded by Greece and the European Union (European Regional Development Fund), grant number MIS 5002697.