Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/939
AuthorsFerreira, T.* 
Gaspar, J. L.* 
Viveiros, F.* 
Marcos, M.* 
Faria, C.* 
Sousa, F.* 
TitleMonitoring of fumarole discharge and CO2 soil degassing in the Azores: contribution to volcanic surveillance and public health risk assessment
Issue Date2005
Series/Report no.48 (4-5)
URIhttp://hdl.handle.net/2122/939
Keywordsvolcanology
geochemistry
soil degassing
monitoring
risk
Subject Classification04. Solid Earth::04.08. Volcanology::04.08.01. Gases 
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring 
AbstractFluid geochemistry monitoring in the Azores involves the regular sampling and analysis of gas discharges from fumaroles and measurements of CO2 diffuse soil gas emissions. Main degassing areas under monitoring are associated with hydrothermal systems of active central volcanoes in S. Miguel, Terceira and Graciosa islands. Fumarole discharge analysis since 1991 show that apart from steam these gas emissions are CO2 dominated with H2S, H2, CH4 and N2 in minor amounts. Mapping of CO2 diffuse soil emissions in S. Miguel Island lead to the conclusion that some inhabited areas are located within hazard-zones. At Furnas village, inside Furnas volcano caldera, about 62% of the 896 houses are within the CO2 anomaly, 5% being in areas of moderate to high risk. At Ribeira Seca, on the north flank of Fogo volcano, few family houses were evacuated when CO2 concentrations in the air reached 8 mol%. To assess and analyse the CO2 soil flux emissions, continuous monitoring stations were installed in S. Miguel (2), Terceira and Graciosa islands. The statistical analysis of the data showed that some meteorological parameters influence the CO2 flux. The average of CO2 flux in S. Miguel stations ranges from 250 g/m2/d at Furnas volcano to 530 g/m2/d at Fogo volcano. At Terceira Island it is about 330 g/m2/d and at Graciosa 4400 g/m2/d.
Appears in Collections:Annals of Geophysics

Files in This Item:
File Description SizeFormat 
16Ferreira.pdf1.35 MBAdobe PDFView/Open
Show full item record

Page view(s)

164
Last Week
0
Last month
checked on Jun 23, 2017

Download(s)

623
checked on Jun 23, 2017

Google ScholarTM

Check