Real-time generation of Shake Maps in the Southeastern Alps.

The aim of this study is the real-time generation of ShakeMaps in the southeastern Alps area. The ShakeMap software has been adapted to the southeastern Alps region and implemented to obtain a stable interface with the Antelope acquisition system in order to extract the ground-motion parameters from the waveforms and to generate ShakeMaps within 5 min of the earthquake occurrence. To evaluate the influence of the station density, synthetic seismograms are computed for the Bovec (northwest Slovenia) 2004 earthquake, and various ShakeMaps are generated by varying the grid size of the simulated recording stations. The results indicate that a dense and uniform spatial distribution of stations in the field is essential to produce accurate ShakeMaps, and the present density of stations in central Friuli is sufficient for a reliable estimate of the extent of the area of strongest shaking. The related maps are generated in real time or quasi-real time using the region-specific ground-motion predictive equations and empirical relations that predict the macroseismic intensity from the recorded ground motion. The model is validated by comparison between observed data and ShakeMap results for both weak motions (Claut 2007 earthquake) and strong motions (Bovec 1998 earthquake).