Fig. 3: Tephra volumes and ground tilt.

a Thermal images taken by the same camera located ~450 m from the craters showing the different scale of intensity of the explosive eruptions at Stromboli based on the temperature, column height and product dispersal. The images show examples of regular Strombolian activity (left frame), the major explosion that occurred on 08 November 2009 (central frame), and the 15 March 2007 paroxysm (right frame). b Logarithmic plot of the volume of erupted product and ground tilt for regular Strombolian activity, major explosions and paroxysms. Tilt error bars for Strombolian activity are based on >10,000 observed events, and those for major explosions are estimated based on the 39 major eruptions that occurred from 2005 to 2019. The average volume for paroxysms (circle) is based on measurements (diamonds) from the 2003 and 2007 events (data are from refs. ^20,25), whereas the volumes of the 2019 paroxysms are estimated on the single exponential decay law from the loading per unit area of fallout deposits versus isomass area plots⁵⁴.