Italian Radon mOnitoring Network (IRON): A permanent network for near real-time monitoring of soil radon emission in Italy

We introduce the Italian Radon mOnitoring Network (IRON): a new nationwide permanent network for near real-time measurements of soil radon emissions in Italy. Deployed over the last 8 years, presently IRON consists of 26 stations mainly concentrated in the Central-Southern Apennines, but marginally covering the whole Italian peninsula. At present, most IRON stations have recorded radon concentration time-series for more than 4-5 years. With a standard sampling interval of about two hours, the whole IRON dataset consists of nearly 440,000 single radon concentration measurements. Here we present the network in terms of sites, installations types and collected time-series. The amount of data, together with the systematic methods of measurements, allowed us to evaluate some significant aspects related both to the measurement methodology and to the complex dynamics of soil radon emanations. Two case studies show, respectively, how different observational setups we implemented impact on the features of the recorded signal, and how observed fluctuations in radon concentration may be ascribed to geophysical processes taking place at depth in the crust. We discuss the potential suitability of IRON, in order to study the relation between radon variability and the preparation processes of strong earthquakes