01933pab a2200157 454500 180718b2002 xxu||||| |||| 00| 0 eng d Pizzino, L. Natural gas hazard (CO2, 222Rn) within a Quiescent volcanic regionand its relations with tectonics: the case of the Ciampin-Marino Area, Albaan Hills Volcano, Italy 2002 p.257-87. Nov Groundwater surveys were performed by detailed (around 300 sites) grid-analysis of water temperature, pH, redox potential, electrical conductivity, 22Rn, alkalinity and by calculating the PCOs, throughout the Ciampino and Marino towns in the Alban Hills quiescent volcano (Central Italy). Following several episodes of dangerous COs exhalation from soils during the last 20 years and earlier as historically record3ed, the work aimed at assessing the Natural Gas Hazard (NGH) including the indoor-Rn hazard. The NGH was defined as the probability of an area to become a site of poisonous peri-volcanic gas exhalations from soils to the lower atmosphere (comprising buildings). CO2 was found to be a "carrier" for the other poisonous minor and in trace components (H2S, CH4, 222Rn, etc.). This assessment was performed by extrapolating in the aquifer CO2 and 222Rn conditions, and discriminating sectors where future CO2 flux in soils as well as indoor-Rn measurements have to be noted. A preliminary indoor-Rn survey was performed at about 200 sites. The highest values were found in the highest pCO2 and high 222Rn values in groundwater. This indicates convecytion and enhanced permeability in certain sectors of the main aquifer, i.e., along the bordering faults and inside the gap-trap of the Ciampino Horst., where "continuous gas-phase micro-macro seepage mechanism" is invoked to explain the high peri-volcanic gases flux. - Reproduced. Gas resources Natural Hazards 54753 54753 54753 0 0 0 0 IIPA IIPA 2018-07-19 Volume no: 27, Issue no: 3 AR55198 2018-07-19 2018-07-19 AR