Relationship between tremor and volcanic activity during the Southeast Crater eruption on Mount Etna in early 2000

摘要

The Southeast Crater of Mount Etna (Italy) was characterized by a violent eruptiveactivity between 26 January and 24 June 2000. This activity produced 64 lava fountainepisodes with repose periods from 3 hours to 10 days. We estimated a volume of about15–20 106 m3 lava and at least 2–3 106 m3 of tephra. We compared theparoxysmal volcanic activity to its associated seismic signature: The high number ofevents highlighted a strict correlation between tremor and volcanic activity. Seismic andvolcanic characteristics, such as the frequency of occurrence, the duration of lavafountains and the associated tremor energy, suggested the subdivision of the studiedperiod into two stages separated by the 20 February event. Combining volcanic withseismic data, we observed some useful relationships among lava fountain height,sustained column height and Reduced Displacement; in addition, we found that the entireepisode was well correlated with the duration of the amplitude increase. Computing thetremor energy linked to each event, the total energy associated with lava fountainsepisodes results in 76% of the energy released during the whole period. Finally, thedifferent ratios among the overall spectral amplitude of the seismic signals of the stationslocated at different altitudes suggested to us the elaboration of a simple qualitative modelto explain the dynamic behavior of the tremor source during the whole episode.