ABSTRACT

The Mw 6.2 Amatrice earthquake that struck central Italy on 24 August 2016 was recorded by seven infrasound arrays in the Euro‐Mediterranean region at distances up to 1260 km. Most stations recorded long‐lasting coherent wavetrains characterized by large back‐azimuth variations. The backprojection of the stratospherically ducted infrasound recorded at five arrays illuminates radiating regions over 600  km along the Apennines from the Po basin to the Gulf of Naples. A comparison between the acoustic surface pressure derived from infrasound records and the seismic source pressure derived from measured seismic ground motion shows first‐order agreement in the attenuation with the epicentral distance. From these observations, seismic quality factors in central Italy are estimated. The northernmost reconstructed source region comprises the Po Valley where seismic amplification occurred within the plain alluvial sediments. These results show that infrasound records at hundreds of kilometers from a shallow moderate magnitude devastating earthquake can provide ground shaking information as well as local amplification caused by topographic and geological features.

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