By analyzing twenty years of eruptive activity, researchers have revealed the relationship between ground deformations and processes connected to the power system of the Sicilian volcano
Over the last 21 years, theEtna it went through several eruptive cycles that gave rise to 26 periods of swelling of the volcanic edifice (so-called "inflation") it's at 14 deflation stages ("deflation"). This is what emerges from a study conducted by a team of researchers fromNational Institute of Geophysics and Volcanology (INGV) and University of Palermo, recently published in the magazine Communication Earth & Environment.
Thanks to the analysis of GNSS data time series (Global Navigation Satellite System) acquired on the Sicilian volcano and the analytical modeling of the ground deformations associated with each phase of inflation or deflation, the researchers were able to characterize the various eruptive cycles, also identifying the position, geometry and volumetric variation of the active magmatic reservoirs along the system of Etna's power supply.
“For the last 21 years or so 10,7 million cubic meters of magma entered the Etna power system annually", explains Mimmo Palano, Researcher at INGV and Associate Professor of Geophysics at the University of Palermo, co-author of the study. “Of all this magma, however, only 28,5% contributed to the eruptive activity, while the remaining 71,5% accumulated inside the volcano, contributing to its swelling”.
I magmatic reservoirs they were identified by researchers beneath the summit area of Etna, at a depth between 3 and 9 km below mean sea level. In particular, those active during periods of inflation are generally located at depths between 4 and 9 km, while those active during periods of deflation are found in the depth range between 3 and 6 km.
“Geodetic data and modeling results show a vertical and horizontal growth of the volcanic edifice during almost the entire time period analyzed", he adds Claudio Chiarabba, Director of the Earthquake Department of INGV and co-author of the study. “Despite short and local phases of subsidence linked to periods of deflation, the vertical growth of the volcanic edifice can be quantified as approximately 9-12 cm. However, while the GNSS stations installed around the summit area show drops of up to 11 mm/year, the variations in horizontal distance between some stations installed on the sides of Etna instead show positive growth rates of up to 20,7 mm/year. This means that Etna's volumetric growth occurs only horizontally".
“The horizontal deformation field of the volcano is largely dominated by the continuum eastward sliding of Etna's eastern flank", goes on Joseph Pezzo, INGV researcher and co-author of the study. “This movement therefore has a key role in the dynamics of the volcano, indicating a progressive depressurization of the crust under the summit area which favors the rise of deep magma and its progressive accumulation along the volcano's feeding system”.
The results of this study are of particular interest since rapid and accurate estimates of the quantity of magma accumulated under active volcanoes such as Etna can contribute to land management and the correct assessment of volcanic risk.
Useful links:
National Institute of Geophysics and Volcanology
Over the last 21 years, theEtna it went through several eruptive cycles that gave rise to 26 periods of swelling of the volcanic edifice (so-called "inflation") it's at 14 deflation stages ("deflation"). This is what emerges from a study conducted by a team of researchers fromNational Institute of Geophysics and Volcanology (INGV) and University of Palermo, recently published in the magazine Communication Earth & Environment.
Thanks to the analysis of GNSS data time series (Global Navigation Satellite System) acquired on the Sicilian volcano and the analytical modeling of the ground deformations associated with each phase of inflation or deflation, the researchers were able to characterize the various eruptive cycles, also identifying the position, geometry and volumetric variation of the active magmatic reservoirs along the system of Etna's power supply.
“For the last 21 years or so 10,7 million cubic meters of magma entered the Etna power system annually", explains Mimmo Palano, Researcher at INGV and Associate Professor of Geophysics at the University of Palermo, co-author of the study. “Of all this magma, however, only 28,5% contributed to the eruptive activity, while the remaining 71,5% accumulated inside the volcano, contributing to its swelling”.
I magmatic reservoirs they were identified by researchers beneath the summit area of Etna, at a depth between 3 and 9 km below mean sea level. In particular, those active during periods of inflation are generally located at depths between 4 and 9 km, while those active during periods of deflation are found in the depth range between 3 and 6 km.
“Geodetic data and modeling results show a vertical and horizontal growth of the volcanic edifice during almost the entire time period analyzed", he adds Claudio Chiarabba, Director of the Earthquake Department of INGV and co-author of the study. “Despite short and local phases of subsidence linked to periods of deflation, the vertical growth of the volcanic edifice can be quantified as approximately 9-12 cm. However, while the GNSS stations installed around the summit area show drops of up to 11 mm/year, the variations in horizontal distance between some stations installed on the sides of Etna instead show positive growth rates of up to 20,7 mm/year. This means that Etna's volumetric growth occurs only horizontally".
“The horizontal deformation field of the volcano is largely dominated by the continuum eastward sliding of Etna's eastern flank", goes on Joseph Pezzo, INGV researcher and co-author of the study. “This movement therefore has a key role in the dynamics of the volcano, indicating a progressive depressurization of the crust under the summit area which favors the rise of deep magma and its progressive accumulation along the volcano's feeding system”.
The results of this study are of particular interest since rapid and accurate estimates of the quantity of magma accumulated under active volcanoes such as Etna can contribute to land management and the correct assessment of volcanic risk.
Useful links:
National Institute of Geophysics and Volcanology
Figure: a) Secular velocity field for Etna Volcano estimated from GNSS data. The colored diamonds identify the magmatic sources modeled for the inflation (red diamonds) and deflation (blue diamonds) phases and are sized according to the estimated volumes. b) Section A-A' showing the P-wave velocity variations and the modeled magmatic sources. c) Time series of the distance variation between the EDAM-ESLN stations, installed respectively to the north and south of the crater area. d) Time series of estimated volumes, inflation (ΔVi), deflation (ΔVo), and resulting budget (ΔVb) phases.