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Instituto de Investigação
em Vulcanologia e Avaliação de Riscos
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Artigos em livros de actas ► Nacionais


Referência Bibliográfica

MORENO, L., VIVEIROS, F., COUTO, R., SILVA, C., RANGE, P., GERALDES, D., PACHECO, J.E. (2016) – Chemical composition of submarine degassing areas in São Miguel Island (Azores archipelago). Actas das 4as Jornadas de Engenharia Hidrográfica, Instituto Hidrográfico, 317-319.


​Several secondary manifestations of volcanism are found in the Azores archipelago including subaerial and submarine hydrothermal fumaroles. This work shows the chemical composition of some submarine degassing vents located offshore of São Miguel Island, namely close to Porto Formoso, Ribeira Quente and Mosteiros villages. The samples were collected during the summers of 2013 and 2014 and spring of 2015. Analytical procedures included gas chromatography for the gases in the headspace of the Giggenbach bottles (CH4, N2, O2, Ar, He and H2) andtitration for those dissolved in the alkaline solution (CO2 and H2S). The dry phase is dominated by CO2 with more than 99 molar%. N2, O2 and Ar are also detected in minor amountsin all the samples, whereas H2and H2 are present only in some of them. Characterization of these degassing emissions is important to identify and quantify the gases emitted and to identify future signals of volcanic activity.