View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Earth-prints Repository Hazardous gas emissions from the flanks of the quiescent Colli Albani volcano (Rome, Italy) M. L. Carapezza1* , F. Barberi2, L. M. Ranaldi2, T. Ricci1, Tarchini2, J. Barrancos3, C. Fischer4, D. Granieri1, C. Lucchetti2, G. Melian3, N. Perez3, P. Tuccimei2, A. Vogel4, K. Weber4 1 Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy; 2 Department of Geological Sciences, Roma Tre University, L.go San L. Murialdo 1, 00146 Rome, Italy; 3 Environmental Research Division, Instituto Tecnologico y de Energias Renovables (ITER), 38594 Granadilla, Tenerife, Spain; 4 Environmental Measurement Techniques, University of Applied Sciences Düsseldorf, Josef-Gockeln-Str. 9, D-40474 Düsseldorf, Germany. *Corresponding author, E-mail:
[email protected], Tel. +39 0651806370, Fax +39 065041181 Abstract Gas 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.