The paroxysmal sequence that occurred during December 13-14, 2020 - February 21, 2022 at Mt. Etna volcano is constituted of 62 lava fountain events. In this work, we propose a multidisciplinary study based on tilt deformation and volcanic tremor RMS amplitude time series using data registered, throughout the whole sequence, by the permanent seismic and tilt networks run by Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Etneo. We retrieved the amount of deflations associated with the fountaining activity, inflations related to the intra-event time, the maxima peaks of volcanic tremor RMS amplitude and a slope parameter to quantify the evolution velocity of each of these phases. We have identified 3 sub-periods based on the deformation patterns and volcanological data. Analysis of the calculated data for both deformation and volcanic tremor RMS amplitude signals showed meaningful differences among the three sub-periods, reflecting magma storage and transport dynamics. During the first period, associated to the February - April 2021 activity, overall medium-high values have been registered for the complete set of parameters considered, indicating higher volumes of volatile-rich magmas transferred from the deeper to the upper portions of the plumbing system. During the second period (May - June 2021) lava fountains were characterized by lower durations, on average, and the lowest values registered during the whole eruptive sequence, with lower volumes and deformations and with slower development of the phenomena. This behavior during the May – June 2021 period could be strictly related to minor amounts of undegassed magmas in the uppermost feeding system, as also confirmed by SO2 data acquired through the continuous gas monitoring network. During the third period (July - October 2021) an increasing trend of the above cited parameters, coupled with decreasing inflation velocity, has been observed. Detailed elaborations of tilt signals and volcanic tremor RMS amplitudes have revealed peculiar behaviors for episodes belonging to the second period, which are characterized by marked inflations right before the onset of lava fountains and periodic RMS amplitude patterns. This approach allowed the investigation of differences in the eruptive style and evolution of the paroxysmal episodes observed at Mt. Etna during the 2020-2022 sequence, inferring some of the magmatic processes and magma transfers dynamics that have determined the distinct features observed during the summit eruptions.
Patterns of tilt deformation and volcanic tremor reveal changing dynamics during the 2020-22 fountaining activity at Mt. Etna
Cardone M.;Cannata A.;Gambino S.;Giuffrida M.;Iozzia A.;Minio V.;Viccaro M.
2023-01-01
Abstract
The paroxysmal sequence that occurred during December 13-14, 2020 - February 21, 2022 at Mt. Etna volcano is constituted of 62 lava fountain events. In this work, we propose a multidisciplinary study based on tilt deformation and volcanic tremor RMS amplitude time series using data registered, throughout the whole sequence, by the permanent seismic and tilt networks run by Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Etneo. We retrieved the amount of deflations associated with the fountaining activity, inflations related to the intra-event time, the maxima peaks of volcanic tremor RMS amplitude and a slope parameter to quantify the evolution velocity of each of these phases. We have identified 3 sub-periods based on the deformation patterns and volcanological data. Analysis of the calculated data for both deformation and volcanic tremor RMS amplitude signals showed meaningful differences among the three sub-periods, reflecting magma storage and transport dynamics. During the first period, associated to the February - April 2021 activity, overall medium-high values have been registered for the complete set of parameters considered, indicating higher volumes of volatile-rich magmas transferred from the deeper to the upper portions of the plumbing system. During the second period (May - June 2021) lava fountains were characterized by lower durations, on average, and the lowest values registered during the whole eruptive sequence, with lower volumes and deformations and with slower development of the phenomena. This behavior during the May – June 2021 period could be strictly related to minor amounts of undegassed magmas in the uppermost feeding system, as also confirmed by SO2 data acquired through the continuous gas monitoring network. During the third period (July - October 2021) an increasing trend of the above cited parameters, coupled with decreasing inflation velocity, has been observed. Detailed elaborations of tilt signals and volcanic tremor RMS amplitudes have revealed peculiar behaviors for episodes belonging to the second period, which are characterized by marked inflations right before the onset of lava fountains and periodic RMS amplitude patterns. This approach allowed the investigation of differences in the eruptive style and evolution of the paroxysmal episodes observed at Mt. Etna during the 2020-2022 sequence, inferring some of the magmatic processes and magma transfers dynamics that have determined the distinct features observed during the summit eruptions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
