Seismic signature of an extreme hydro-meteorological event in Italy

Flashfloods are a major threat for Mediterranean countries and their frequency is expected to increasein the next years due to the climatic change. Civil protection agencies are called to deal with increasinghydrological risk, but existing hydro-meteorological monitoring networks might not be enough fordetecting, tracking, and characterizing rapidly evolvingfloods produced by severe convective storms.Nowadays, hydro-meteorological information in several watersheds particularly in small and mid-sizein orographically complex regions or in third-world countries, is still not available or insufficient. Toimprove our observational capability of these events, we propose to exploit the seismic recordings,which act as opportunistic signals and can complement well-established procedures to early detectthe occurrence offlashfloods at regional scale. Here, we investigate the hydro-meteorological eventthat hit central Italy in September 2022 and resulted in a devastatingflashflood. We compare seismicdata from anationalmonitoring networkwithraingaugesand hydrometerdata. Ourevidencesuggeststhat the main stages of the hydro-meteorological events can be tracked by the spatio-temporalevolution of the seismic noise confirming the capability of this multi-sensor approach in detecting andcharacterizing such kind of events