The mud volcanoes at Santa Barbara and Aragona (Sicily, Italy): Their potential hazards for a correct risk assessment

Abstract. The Santa Barbara and Aragona areas are affected by mud volcanism (MV) phenomena, consisting of continuous or intermittent emission of mud, water and gases. This activity could be interrupted by paroxysmal events, with an eruptive column composed mainly of clay material, water and gases. They are the most hazardous phenomena and, nowadays, it is impossible to define the potential parameters for modeling the phenomenon. In 2017, two DSM were performed by drone in both areas, thus allowing the mapping of the emission zones and the covered areas by the previous events. Detailed information about past paroxysms was obtained from historical sources and, with the analysis of the 2017 DSMs, a preliminary hazard assessment was carried out, for the first time at two sites. Two potentially hazardous paroxysm surfaces of 0.12 km² and 0.20 km² for Santa Barbara and Aragona respectively, were defined. In May 2020, at Aragona, a new paroxysm covered a surface of 8,721 m². After this, a new detailed DSM was collected with the aim to make a comparison with 2017 one. Since 2017, a seismic station was installed at Santa Barbara. From preliminary results, both seismic events and ambient noise showed a frequency of 5–10 Hz.