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Institut de Physique du Globe de Paris, Sorbonne Paris CiteĀ“, UniversiteĀ“ Paris Diderot
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- PublicationRestrictedInsights into Mt. Etnaās Shallow Plumbing System from the Analysis of Infrasound Signals, August 2007āDecember 2009(2015)
; ; ; ; ; ; ; ; ;Spina, L.; Department of Earth and Environmental Sciences, Ludwig Maximilian University ;Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Privitera, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Vergniolle, S.; Institut de Physique du Globe de Paris, Sorbonne Paris CiteĀ“, UniversiteĀ“ Paris Diderot ;Ferlito, C.; Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Sezione Scienze della Terra, Universita` di Catania ;Gresta, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Montalto, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Sciotto, M.; Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Sezione Scienze della Terra, Universita` di Catania; ; ; ; ; ; ; Previous studies performed on Mt. Etna on short and discontinuous time intervals indicate the North East Crater (NEC) as the most active source of infrasound. The source mechanism of NEC infrasound events was modeled as a double resonance. This lead to infer the connection between the NEC and both the southeast crater (SEC) and the eruptive fissure (EF), that opened at the beginning of the 2008ā2009 eruption. Nevertheless, there are still several open questions that need to be addressed. For instance, the steadiness of NEC event features should be studied, as well as the orderliness of spectral changes of NEC events time-related to eruptive activity of other vents. The investigation of such topics is strongly enhanced by the possibility of analysing infrasound signals during year-long time periods. With this aim about 40,000 infrasound events, recorded at Mt. Etna from August 2007 to December 2009 were analysed by using spectral and location techniques. It was noted in particular that the NEC events featured periods with very steady waveforms and spectral characteristics lasting from days to months with slow or sudden variations. The most important eruptive episodes occurring at the SEC or the EF were accompanied by significant spectral changes in NEC events. In light of such systematic behaviour the connection between the NEC and the SEC/EF plumbing systems was not considered temporary but rather stable even during a relatively long time interval (2006ā2009). Moreover, study of NEC event spectral features and their changes over multiple years supports the double resonance source model. Such a model, together with the inferred connections between NEC and SEC/EF feeding systems, implies that level fluctuations of a magma column inside the NEC conduit correspond to magmastatic pressure decrease/increase inside the main plumbing system. These findings open up new and interesting possibilities for monitoring magma pressure changes inside the Mt. Etna plumbing system.1037 33