Figure 8

(a) Accelerograms of the Mw6.5 Norcia earthquake recorded on the third floor of the INGV-Osservatorio Vesuviano by Episensor FBA-EST Kinemetrics (blue, top panel) and (b) by the optical sensor (red, bottom panel); (c) FFT spectrum of the Norcia earthquake sensed by the LOF sensor (up to 5 Hz) (d) Cross-correlation between the two signals, filtered in the frequency range of 0.1–5 Hz, recorded with the optical sensor and the Episensor (e) PGAs recorded by the INGV accelerometric stations during the 30 October (06:40:17), Mw6.5, mainshock (from ISMD 2.0: http://ismd.mi.ingv.it/⁵⁴).