After the strong volcanic gas release, occurred in 2002 and 2003, in the area near the islets to the east of the Panarea volcanic island, several researches have been carried out to understand the origin, nature and effects of these emissions. These researches evidenced various sites of CO2- rich hydrothermal gas and fluid leakage in the marine area east of Panarea, furthermore, they have given different estimates of total CO2 released by the submarine volcanic system from post-glacial to today. In light of this, the ISMAR-CNR and ISPRA carried out researches between 2013 and 2015 focused on the characterization of the marine hydrothermal field between the island of Panarea and the islet of Basiluzzo (NE of Panarea), from the morphological, biological and chemical-physical point of view, in particular for what concerns the diffusive benthic fluxes. Oceano- graphic cruises allowed to identify and characterize three areas with intense hydrothermal activity. The first area, located on the South-East of the island of Panarea (Secca dei Pesci), is characterized by intense emissions of acidic fluids, rich in DIC, at the same temperature of the surrounding environment, but with weak metal contents. The second area, discovered in 2015, located at the bottom of the slope to the North-East of the island of Panarea, has been called "Smoking Land" due to the presence of about 200 hydrothermal chimneys of considerable size (1-4 m high, with an average base diameter of about 4 m), partly active and partly quiescent. The last area, located to the North-East of the DBLP islets, is characterized by circular depressions, these, too, partly active and partly inactive. In these two last areas, the dissolved benthic flux measurements showed a fragmented patchwork pattern with emissions of acidic fluids, at the same temperature of the surrounding environment, rich in DIC, Fe and other metals (Mn, Zn, Al). These two areas are located at the borders of a depression extended OSO-ENE. They are the result of a hydrothermal circulation of rising volcanic gas, mixed with sea water perculated in the marine crust, along normal faults. Near to the active release areas there are inactive areas, with overpressure gas inside, due to the presence of a Fe-oxides and hydroxides surface layer that prevents the leakage, and quiescent areas for an already occurred degassing. From this set-up derives the need for continuous monitoring to prevent possible future risks for the surrounding areas.
A seguito del violento rilascio di gas, verificatosi nel 2002 e 2003, nell'area prospiciente gli isolotti a est dell'Isola vulcanica di Panarea, sono state condotte numerose ricerche per comprendere l'origine, la natura e gli effetti di queste emissioni. Tali ricerche hanno evidenziato vari punti di rilascio di gas e fluidi idrotermali ricchi di CO2 nell'area di mare a est di Panarea e hanno prodotto diverse stime della CO2 totale rilasciata dal sistema sottomarino a partire dal post-glaciale ad oggi. Alla luce di questo, l'ISMAR-CNR e l'ISPRA hanno condotto delle ricerche specifiche tra il 2013 e il 2015 per caratterizzare il campo idrotermale sommerso compreso tra l'isola di Panarea e l'isolotto di Basiluzzo (NE di Panarea), dal punto di vista morfologico, biologico e chimico- fisico, in particolare per ciò che riguarda i flussi bentici diffusi. Le campagne oceanografiche hanno consentito di individuare e caratterizzare tre aree con intensa attività idrotermale. La prima area, situata a Sud-Est dell'isola di Panarea (Secca dei Pesci), è caratterizzata da un'intensa attività esalativa di fluidi acidi, ricchi di DIC, a temperatura ambiente ma con deboli contenuti in metalli. La seconda area, scoperta nel 2015, situata ai piedi della scarpata a Nord-Est dell'isola di Panarea, è stata denominata Smoking Land per la presenza di circa 200 camini idrotermali di dimensioni consistenti (1-4 m di altezza; circa 4 m in media di diametro di base), in parte attivi e in parte quiescenti. L'ultima area, situata a Nord-Est degli isolotti DBLP, è caratterizzata da depressioni circolari, anche esse in parte attive e in parte inattive. In queste ultime due aree, le misure di flussi bentici disciolti hanno evidenziato un andamento a macchia di leopardo con rilascio di fluidi acidi, a temperatura ambiente, ricchi di DIC, Fe e altri metalli (Mn, Zn, Al). Queste due aree sono localizzate ai margini di un avvallamento allungato in direzione OSO-ENE. Esse sono il risultato di una circolazione idrotermale con risalita, lungo faglie distensive, di gas di origine vulcanica mescolati ad acqua di mare penetrata nel sottofondo marino. Adiacenti alle aree attive sono presenti aree inattive, cariche di gas in sovrappressione per la presenza di uno strato superficiale di ossidi e idrossidi di Fe che ne impedisce la fuoriuscita, e aree quiescenti per una degassificazione già avvenuta. Da questo assetto deriva la necessità di un continuo monitoraggio atto a prevedere possibili future situazioni di pericolo per le aree circostanti.
Nuove recenti conoscenze sul sistema idrotermale del complesso vulcanico dell'Isola di Panarea (Arcipelago delle Eolie, Mar Tirreno Meridionale). New recent insights of the hydrothermal system of the Panarea Island (Aeolian Archipelago, South Tyrrhenian Sea).
Spagnoli F;
2019
Abstract
After the strong volcanic gas release, occurred in 2002 and 2003, in the area near the islets to the east of the Panarea volcanic island, several researches have been carried out to understand the origin, nature and effects of these emissions. These researches evidenced various sites of CO2- rich hydrothermal gas and fluid leakage in the marine area east of Panarea, furthermore, they have given different estimates of total CO2 released by the submarine volcanic system from post-glacial to today. In light of this, the ISMAR-CNR and ISPRA carried out researches between 2013 and 2015 focused on the characterization of the marine hydrothermal field between the island of Panarea and the islet of Basiluzzo (NE of Panarea), from the morphological, biological and chemical-physical point of view, in particular for what concerns the diffusive benthic fluxes. Oceano- graphic cruises allowed to identify and characterize three areas with intense hydrothermal activity. The first area, located on the South-East of the island of Panarea (Secca dei Pesci), is characterized by intense emissions of acidic fluids, rich in DIC, at the same temperature of the surrounding environment, but with weak metal contents. The second area, discovered in 2015, located at the bottom of the slope to the North-East of the island of Panarea, has been called "Smoking Land" due to the presence of about 200 hydrothermal chimneys of considerable size (1-4 m high, with an average base diameter of about 4 m), partly active and partly quiescent. The last area, located to the North-East of the DBLP islets, is characterized by circular depressions, these, too, partly active and partly inactive. In these two last areas, the dissolved benthic flux measurements showed a fragmented patchwork pattern with emissions of acidic fluids, at the same temperature of the surrounding environment, rich in DIC, Fe and other metals (Mn, Zn, Al). These two areas are located at the borders of a depression extended OSO-ENE. They are the result of a hydrothermal circulation of rising volcanic gas, mixed with sea water perculated in the marine crust, along normal faults. Near to the active release areas there are inactive areas, with overpressure gas inside, due to the presence of a Fe-oxides and hydroxides surface layer that prevents the leakage, and quiescent areas for an already occurred degassing. From this set-up derives the need for continuous monitoring to prevent possible future risks for the surrounding areas.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
