Radon mapping, automatic measurements and extremely high 222Rn emissions during the 2002–2007 eruptive scenarios at Stromboli volcano

We report additional radon data collected at Stromboli during 2002–2007. The whole data set of periodic measurements has been systematically analyzed to retrieve the values of background, threshold and anomaly for all the stations of the network. Maps of radon concentrations in space and time correlate with changes in volcanic activity. Higher radon emissions are essentially concentrated at summit stations and may also affect some stations located onto the summit-eastern sector of the cone (along the N60°E fracture zone), as well as two stations placed at the NE edge of Sciara del Fuoco.Most of these stations are well above their threshold values during effusive eruptions (namely 2002–2003 and 2007) due to the progressive structural adjustment of the volcano edifice coupled with the opening and resetting of the fracture network.