Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/7620
AuthorsCarapezza, M. L.* 
Barberi, F.* 
Ranaldi, L. M.* 
Ricci, T.* 
Tarchini, L.* 
Barrancos, J.* 
Fischer, C.* 
Granieri, D.* 
Lucchetti, C.* 
Melian, G.* 
Perez, N.* 
Tuccimei, P.* 
Vogel, A.* 
Weber, K.* 
TitleHazardous gas emissions from the flanks of the quiescent Colli Albani volcano (Rome, Italy)
Issue Date2012
Series/Report no.9/27 (2012)
DOI10.1016/j.apgeochem.2012.02.012
URIhttp://hdl.handle.net/2122/7620
Keywordsgas hazard
hydrogen sulfide
carbon dioxide
Colli Albani volcano
Subject Classification04. Solid Earth::04.08. Volcanology::04.08.01. Gases 
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring 
04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques 
AbstractGas hazard was evaluated in the three most important cold gas emission zones on the flanks of the quiescent Colli Albani volcano. These zones are located above structural highs of the buried carbonate basement which represents the main regional aquifer and the main reservoir for gas rising from depth. All extensional faults affecting the limestone reservoir represent leaking pathways along which gas rises to the surface and locally accumulates in shallow permeable horizons forming pressurized pockets that may produce gas blowout when reached by wells. The gas, mainly composed by CO2 (>90 vol.%), contains appreciable quantities of H2S (0.35-6 vol.%), and both represent a potentially high local hazard. Both gases are denser than air and accumulate near ground where they may reach hazardous concentrations, and actually lethal accidents frequently occur to animals watering at local ponds. In order to evaluate the rate of degassing and the related hazard, CO2 and H2S diffuse soil flux surveys have been repeatedly carried out by accumulation chamber. The viscous gas flux of some important discrete emissions has been also evaluated and the CO2 and H2S air concentration measured by portable devises and by Tunable Diode Laser profiles. The minimum potential lethal concentration of the two gases (250 ppm for H2S and 8 vol.% for CO2) is 320 times higher for CO2, whereas the CO2/H2S concentration ratio in the emitted natural gas is significantly lower (15-159). This explains why H2S reaches hazardous, even lethal, concentrations more frequently than CO2. A relevant hazard exists for both gases in the depressed zones (channels, excavations) particularly in the non-windy early hours of the day.
Appears in Collections:Papers Published / Papers in press

Files in This Item:
File Description SizeFormat 
AG_PP_Carapezza_etal_2011.pdf1.46 MBAdobe PDFView/Open
article.pdf3.41 MBAdobe PDFView/Open    Request a copy
Show full item record

Page view(s)

102
checked on May 27, 2017

Download(s)

272
checked on May 27, 2017

Google ScholarTM

Check

Altmetric