On November, 3th, 2002 a huge submarine volcanic-hydrothermal gas burst started nearby Bottaro islet (Panarea, Eolian Islands). Direct underwater surveys of the new gas vents were performed up to 40 meters below the sea surface. We adopted the available high resolution Marine Digital Terrain Model (MDTM), obtained by multibeam technique (average pixel of 0.5 m) to identifies: i) the location of the exhalative centres, ii) the dimesion of the exhalative centres, iii) areas that show a morphology similar to the active exhalative centres; iiii) the role of N240- and N310-trending fractures.Geochemical surveys of the underwater gas samples were collected by a plastic funnel placed on the gas vents during surveys performed by scientific divers. The funnel is connected to a Pyrex glass flask equipped with twin valves and filled with air at a pressure higher than the hydrostatic expected, to avoid the sea water contamination during sampling. The same device was used to collect the gas samples in NaOH 4 M filled flasks. To sample the dissolved gas we used the traditional glass sampler filled with the water close to the vent. Radon was collected by the funnel linked to a special plastic sampler. Hot water samples from the underwater springs were collected by a glass flask equipped with twin valves, vacuumed and connected to a steel hose.. Sulphur bacteria, living close to the hydrothermal springs, have been sampled and analysed by divers using 60 cc syringes during surveys.The available geochemical, geological and geophysical data suggest that the most likely explanation for the November 2002 event is that it represents the parossistic evolution of a hydrothermal system fed by a quasi-steady deep source of magmatic fluids.
Caramanna, G., Anzidei, M., Bortoluzzi, G., Cardellini, F., Cinti, D., Esposito, A., et al. (2004). Scientific diving techniques applied to the investigation of the underwater hydrothermal gas vents of the volcanic area of Panarea Island (Aeolian Islands – South Tyrrenian Sea – Italy): geochemical, morphology and volcanology implications for hazard evaluation.
Scientific diving techniques applied to the investigation of the underwater hydrothermal gas vents of the volcanic area of Panarea Island (Aeolian Islands – South Tyrrenian Sea – Italy): geochemical, morphology and volcanology implications for hazard evaluation
GIORDANO, Guido;
2004-01-01
Abstract
On November, 3th, 2002 a huge submarine volcanic-hydrothermal gas burst started nearby Bottaro islet (Panarea, Eolian Islands). Direct underwater surveys of the new gas vents were performed up to 40 meters below the sea surface. We adopted the available high resolution Marine Digital Terrain Model (MDTM), obtained by multibeam technique (average pixel of 0.5 m) to identifies: i) the location of the exhalative centres, ii) the dimesion of the exhalative centres, iii) areas that show a morphology similar to the active exhalative centres; iiii) the role of N240- and N310-trending fractures.Geochemical surveys of the underwater gas samples were collected by a plastic funnel placed on the gas vents during surveys performed by scientific divers. The funnel is connected to a Pyrex glass flask equipped with twin valves and filled with air at a pressure higher than the hydrostatic expected, to avoid the sea water contamination during sampling. The same device was used to collect the gas samples in NaOH 4 M filled flasks. To sample the dissolved gas we used the traditional glass sampler filled with the water close to the vent. Radon was collected by the funnel linked to a special plastic sampler. Hot water samples from the underwater springs were collected by a glass flask equipped with twin valves, vacuumed and connected to a steel hose.. Sulphur bacteria, living close to the hydrothermal springs, have been sampled and analysed by divers using 60 cc syringes during surveys.The available geochemical, geological and geophysical data suggest that the most likely explanation for the November 2002 event is that it represents the parossistic evolution of a hydrothermal system fed by a quasi-steady deep source of magmatic fluids.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
