{"id":{"repo_id":"catania","oai_identifier":"oai:www.iris.unict.it:20.500.11769/587915"},"canonical_url":"https://search.dev.ndltd.org/etd/catania/oai:www.iris.unict.it:20.500.11769/587915","repository":{"repo_id":"catania","name":"Università degli Studi di Catania","base_url":"https://www.iris.unict.it/oai/request"},"display":{"title":"Investigation on Mt. Etna dynamics by seismic and acoustic signals (August 2007-December 2010)","abstract":"In order to shed light on the dynamics of the plumbing system, and define the source-mechanism of acoustic events at Mt. Etna, infrasound signals-continuously recorded by Istituto Nazionale di Geofisica and Vulcanologia- were analyzed in this thesis, jointly with some seismic signals. In particular, we focused on the period comprised between August 2007 and December 2010, during which a wide spectrum of eruptive activity occurred. Until the activation of Bocca Nuova (BN), on August 2010, the three main vents radiating infrasound were North East Crater (NEC), South East Crater (SEC), and the Eruptive Fissure of the 2008-2009 eruption (EF). Location and spectral analyses carried out on the infrasound signals, revealed the numerical dominance and the steadiness of NEC events, radiating almost continuously acoustic energy, oppositely to SEC and EF. Furthermore, NEC events most relevant changes (spectral and amplitude variation) occurred systematically after the renewal of activity at SEC or at the EF. This evidence led us to infer the existence of a persistent link among their feeding system, and confirm the presence of a double resonance model for NEC events. Successively, events from EF were gathered and analyzed in detail through high precision location methods, allowing to define the cyclic activation of an highest altitude vent along the fissure, likely corresponding to the arrival of new batch of magma, rich in volatiles. During 2010, instead, Mt. Etna eruptive style was different, being characterized by a total number of roughly 35 minor ash emissions from SEC, BN and NEC. Three main episodes are here analyzed, by studying the morphological and compositional features of the sampled ash and the seismic and acoustic signals radiated during those events. Different conditions were deduced for the craters. In particular, for SEC and BN the presence of material plugging the upper conduit was inferred, while data shows that NEC was characterized by open conduit conditions. Finally, a dataset of acoustic signals, regarding few days of explosive activity occurring at Mt. Yasur (Vanuatu) was analyzed. Indeed, the comparison with other volcanic environments is fundamental in order to widen the knowledge on the volcanic phenomena. Mt. Yasur data, revealed completely different features, suggesting that different source dynamics were active. Furthermore, the existence of propagation effects, affecting the signals ́ characteristics and due to the topography is discussed.","abstract_html":"In order to shed light on the dynamics of the plumbing system, and define the source-mechanism of acoustic events at Mt. Etna, infrasound signals-continuously recorded by Istituto Nazionale di Geofisica and Vulcanologia- were analyzed in this thesis, jointly with some seismic signals. In particular, we focused on the period comprised between August 2007 and December 2010, during which a wide spectrum of eruptive activity occurred. Until the activation of Bocca Nuova (BN), on August 2010, the three main vents radiating infrasound were North East Crater (NEC), South East Crater (SEC), and the Eruptive Fissure of the 2008-2009 eruption (EF). Location and spectral analyses carried out on the infrasound signals, revealed the numerical dominance and the steadiness of NEC events, radiating almost continuously acoustic energy, oppositely to SEC and EF. Furthermore, NEC events most relevant changes (spectral and amplitude variation) occurred systematically after the renewal of activity at SEC or at the EF. This evidence led us to infer the existence of a persistent link among their feeding system, and confirm the presence of a double resonance model for NEC events. Successively, events from EF were gathered and analyzed in detail through high precision location methods, allowing to define the cyclic activation of an highest altitude vent along the fissure, likely corresponding to the arrival of new batch of magma, rich in volatiles. During 2010, instead, Mt. Etna eruptive style was different, being characterized by a total number of roughly 35 minor ash emissions from SEC, BN and NEC. Three main episodes are here analyzed, by studying the morphological and compositional features of the sampled ash and the seismic and acoustic signals radiated during those events. Different conditions were deduced for the craters. In particular, for SEC and BN the presence of material plugging the upper conduit was inferred, while data shows that NEC was characterized by open conduit conditions. Finally, a dataset of acoustic signals, regarding few days of explosive activity occurring at Mt. Yasur (Vanuatu) was analyzed. Indeed, the comparison with other volcanic environments is fundamental in order to widen the knowledge on the volcanic phenomena. Mt. Yasur data, revealed completely different features, suggesting that different source dynamics were active. Furthermore, the existence of propagation effects, affecting the signals ́ characteristics and due to the topography is discussed.","abstract_has_math":false,"creators":["SPINA, LAURA"],"institution":"Università degli studi di Catania","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["GRESTA, Stefano","MONACO, Carmelo Giovanni"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-12-05","date_published":"2013-12-05","updated_at":"2026-07-24T01:35:03Z","subjects":["infrasound, plumbing system, resonance, Etna"],"languages":["eng"],"rights":["info:eu-repo/semantics/openAccess","license:PUBBLICO - Pubblico con Copyright","license uri:iris.PUB02"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/20.500.11769/587915","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Spina, Laura","GRESTA, Stefano","MONACO, Carmelo Giovanni"]},{"key":"dc:creator","label":"Author","values":["SPINA, LAURA"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-12-05"]},{"key":"dc:publisher","label":"Institution","values":["Università degli studi di Catania","place:Catania"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["infrasound, plumbing system, resonance, Etna"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess","license:PUBBLICO - Pubblico con Copyright","license uri:iris.PUB02"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/20.500.11769/587915"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In order to shed light on the dynamics of the plumbing system, and define the source-mechanism of acoustic events at Mt. Etna, infrasound signals-continuously recorded by Istituto Nazionale di Geofisica and Vulcanologia- were analyzed in this thesis, jointly with some seismic signals. In particular, we focused on the period comprised between August 2007 and December 2010, during which a wide spectrum of eruptive activity occurred. Until the activation of Bocca Nuova (BN), on August 2010, the three main vents radiating infrasound were North East Crater (NEC), South East Crater (SEC), and the Eruptive Fissure of the 2008-2009 eruption (EF). Location and spectral analyses carried out on the infrasound signals, revealed the numerical dominance and the steadiness of NEC events, radiating almost continuously acoustic energy, oppositely to SEC and EF. Furthermore, NEC events most relevant changes (spectral and amplitude variation) occurred systematically after the renewal of activity at SEC or at the EF. This evidence led us to infer the existence of a persistent link among their feeding system, and confirm the presence of a double resonance model for NEC events. Successively, events from EF were gathered and analyzed in detail through high precision location methods, allowing to define the cyclic activation of an highest altitude vent along the fissure, likely corresponding to the arrival of new batch of magma, rich in volatiles. During 2010, instead, Mt. Etna eruptive style was different, being characterized by a total number of roughly 35 minor ash emissions from SEC, BN and NEC. Three main episodes are here analyzed, by studying the morphological and compositional features of the sampled ash and the seismic and acoustic signals radiated during those events. Different conditions were deduced for the craters. In particular, for SEC and BN the presence of material plugging the upper conduit was inferred, while data shows that NEC was characterized by open conduit conditions. Finally, a dataset of acoustic signals, regarding few days of explosive activity occurring at Mt. Yasur (Vanuatu) was analyzed. Indeed, the comparison with other volcanic environments is fundamental in order to widen the knowledge on the volcanic phenomena. Mt. Yasur data, revealed completely different features, suggesting that different source dynamics were active. Furthermore, the existence of propagation effects, affecting the signals ́ characteristics and due to the topography is discussed.","Allo scopo di far luce sulle dinamiche del sistema di alimentazione e definire i meccanismi sorgente degli eventi acustici al Mt. Etna, sono stati analizzati i segnali infrasonici registrati, continuativamente, dall ́Istituto Nazionale di Geofisica e Vulcanologia, insieme ad alcuni segnali sismici correlati. In particolare, é stato analizzato il periodo compreso tra Agosto 2007 e Dicembre 2010, durante il quale un ampio spettro di attivitá eruttiva ha avuto luogo. Fino all ́attivazione, nell`agosto del 2010, di Bocca Nuova (BN), tre principali sorgenti di infrasuono sono state osservate: il cratere di Nord Est (NEC), il cratere di Sud Est (SEC) e la fessura eruttiva relativa all ́eruzione 2008-2009 (EF). Mediante analisi di localizzazione e analisi spettrale del segnale infrasonico, si é potuta identificare la dominanza numerica e la stabilitá degli eventi del NEC, che irradia in maniera pressoché continua energia acustica. Inoltre, le principali variazioni degli eventi del NEC (cambiamenti spettrali e di ampiezza) hanno avuto luogo sistematicamente dopo la ripresa di attivitá al SEC o ad EF. Questa evidenza consente di affermare la presenza di un link persistente tra i sistemi di alimentazione delle suddette bocche, e conferma il modello della doppia risonanza ipotizzato per gli eventi del NEC. Successivamente, eventi della EF sono stati selezionati ed analizzati in dettaglio mediante localizzazione di alta precisione. Ció ha consentito di definire la presenza di cicli di attivazione di una bocca posta a maggiore altitudine lungo la fessura eruttiva, che rifletterebbero l ́arrivo periodico di nuovo magma, ricco in volatili. Durante il 2010 invece, un numero di circa 35 esplosioni di minore entitá hanno avuto luogo al SEC, BN e NEC. Tre principali episodi sono stati analizzati nel presente lavoro, studiando le caratteristiche morfologiche e composizionali della cenere campionata, ed i segnali sismici ed acustici irradiati durante questi eventi. Differenti condizioni sono state dedotte per i crateri. In particolare, per il SEC e BN si é ipotizzata la presenza di materiale litico ad occlusione della porzione superiore del condotto, mentre i dati mostrano che il NEC é stato caratterizzato da condizioni di condotto aperto. Infine é stato analizzato un dataset di segnali acustici, relativi ad alcuni giorni di attivitá esplosiva del Mt. Yasur (Vanuatu). Infatti, il confronto con altri contesti vulcanici é fondamentale per estendere la conoscenza dei fenomeni eruttivi. I dati del Mt. Yasur hanno rivelato caratteristiche differenti, suggerendo la presenza di diverse dinamiche sorgente. Inoltre, a partire dalle caratteristiche del segnale, la possibile esistenza di effetti di diffrazione al bordo craterico é stato considerata e discussa."]},{"key":"dc:title","label":"Title","values":["Investigation on Mt. Etna dynamics by seismic and acoustic signals (August 2007-December 2010)"]}]}],"canonical_facts":{"dc:contributor":["Spina, Laura","GRESTA, Stefano","MONACO, Carmelo Giovanni"],"dc:creator":["SPINA, LAURA"],"dc:date":["2013-12-05"],"dc:description":["In order to shed light on the dynamics of the plumbing system, and define the source-mechanism of acoustic events at Mt. Etna, infrasound signals-continuously recorded by Istituto Nazionale di Geofisica and Vulcanologia- were analyzed in this thesis, jointly with some seismic signals. In particular, we focused on the period comprised between August 2007 and December 2010, during which a wide spectrum of eruptive activity occurred. Until the activation of Bocca Nuova (BN), on August 2010, the three main vents radiating infrasound were North East Crater (NEC), South East Crater (SEC), and the Eruptive Fissure of the 2008-2009 eruption (EF). Location and spectral analyses carried out on the infrasound signals, revealed the numerical dominance and the steadiness of NEC events, radiating almost continuously acoustic energy, oppositely to SEC and EF. Furthermore, NEC events most relevant changes (spectral and amplitude variation) occurred systematically after the renewal of activity at SEC or at the EF. This evidence led us to infer the existence of a persistent link among their feeding system, and confirm the presence of a double resonance model for NEC events. Successively, events from EF were gathered and analyzed in detail through high precision location methods, allowing to define the cyclic activation of an highest altitude vent along the fissure, likely corresponding to the arrival of new batch of magma, rich in volatiles. During 2010, instead, Mt. Etna eruptive style was different, being characterized by a total number of roughly 35 minor ash emissions from SEC, BN and NEC. Three main episodes are here analyzed, by studying the morphological and compositional features of the sampled ash and the seismic and acoustic signals radiated during those events. Different conditions were deduced for the craters. In particular, for SEC and BN the presence of material plugging the upper conduit was inferred, while data shows that NEC was characterized by open conduit conditions. Finally, a dataset of acoustic signals, regarding few days of explosive activity occurring at Mt. Yasur (Vanuatu) was analyzed. Indeed, the comparison with other volcanic environments is fundamental in order to widen the knowledge on the volcanic phenomena. Mt. Yasur data, revealed completely different features, suggesting that different source dynamics were active. Furthermore, the existence of propagation effects, affecting the signals ́ characteristics and due to the topography is discussed.","Allo scopo di far luce sulle dinamiche del sistema di alimentazione e definire i meccanismi sorgente degli eventi acustici al Mt. Etna, sono stati analizzati i segnali infrasonici registrati, continuativamente, dall ́Istituto Nazionale di Geofisica e Vulcanologia, insieme ad alcuni segnali sismici correlati. In particolare, é stato analizzato il periodo compreso tra Agosto 2007 e Dicembre 2010, durante il quale un ampio spettro di attivitá eruttiva ha avuto luogo. Fino all ́attivazione, nell`agosto del 2010, di Bocca Nuova (BN), tre principali sorgenti di infrasuono sono state osservate: il cratere di Nord Est (NEC), il cratere di Sud Est (SEC) e la fessura eruttiva relativa all ́eruzione 2008-2009 (EF). Mediante analisi di localizzazione e analisi spettrale del segnale infrasonico, si é potuta identificare la dominanza numerica e la stabilitá degli eventi del NEC, che irradia in maniera pressoché continua energia acustica. Inoltre, le principali variazioni degli eventi del NEC (cambiamenti spettrali e di ampiezza) hanno avuto luogo sistematicamente dopo la ripresa di attivitá al SEC o ad EF. Questa evidenza consente di affermare la presenza di un link persistente tra i sistemi di alimentazione delle suddette bocche, e conferma il modello della doppia risonanza ipotizzato per gli eventi del NEC. Successivamente, eventi della EF sono stati selezionati ed analizzati in dettaglio mediante localizzazione di alta precisione. Ció ha consentito di definire la presenza di cicli di attivazione di una bocca posta a maggiore altitudine lungo la fessura eruttiva, che rifletterebbero l ́arrivo periodico di nuovo magma, ricco in volatili. Durante il 2010 invece, un numero di circa 35 esplosioni di minore entitá hanno avuto luogo al SEC, BN e NEC. Tre principali episodi sono stati analizzati nel presente lavoro, studiando le caratteristiche morfologiche e composizionali della cenere campionata, ed i segnali sismici ed acustici irradiati durante questi eventi. Differenti condizioni sono state dedotte per i crateri. In particolare, per il SEC e BN si é ipotizzata la presenza di materiale litico ad occlusione della porzione superiore del condotto, mentre i dati mostrano che il NEC é stato caratterizzato da condizioni di condotto aperto. Infine é stato analizzato un dataset di segnali acustici, relativi ad alcuni giorni di attivitá esplosiva del Mt. Yasur (Vanuatu). Infatti, il confronto con altri contesti vulcanici é fondamentale per estendere la conoscenza dei fenomeni eruttivi. I dati del Mt. Yasur hanno rivelato caratteristiche differenti, suggerendo la presenza di diverse dinamiche sorgente. Inoltre, a partire dalle caratteristiche del segnale, la possibile esistenza di effetti di diffrazione al bordo craterico é stato considerata e discussa."],"dc:identifier":["https://hdl.handle.net/20.500.11769/587915"],"dc:language":["eng"],"dc:publisher":["Università degli studi di Catania","place:Catania"],"dc:rights":["info:eu-repo/semantics/openAccess","license:PUBBLICO - Pubblico con Copyright","license uri:iris.PUB02"],"dc:subject":["infrasound, plumbing system, resonance, Etna"],"dc:title":["Investigation on Mt. Etna dynamics by seismic and acoustic signals (August 2007-December 2010)"],"dc:type":["info:eu-repo/semantics/doctoralThesis"]},"updated_at":"2026-07-24T01:35:03Z"}