Infrasound signals as a discriminating tool for the volcanic activity: Mt. Etna volcano, 16 November 2006

On November 16, 2006, intense strombolian activity took place at Mt. Etna volcano (Italy). According to several researchers this activity culminated with phreatomagmatic explosions, generating pyroclastic density currents. In order to investigate the dynamics of this eruptive episode, infrasound and seismic signals together with visual observations were studied. After comparing visual and acoustic data, a detailed spectral and waveform characterization of the infrasound events was performed. Then, the source mechanisms were investigated by applying strombolian bubble, Helmholtz resonator and vibrating conduit models. Further, in order to follow the dynamics of the magma bodies at depth we also obtained the time variation of the volcanic tremor source location. Finally, the time evolution of the infrasonic energy was compared to the seismic one, showing important differences, that were likely due to time variations of the eruptive dynamics.