Publication Date:
2024-01-25
Description:
The persistent open-vent degassing of Mt. Etna is often punctuated by monthslong
paroxysmal sequences characterized by episodes of violent Strombolian to
lava fountaining activity. Understanding these gas-fueled transitions from
quiescence to eruption requires routine measurement of gas fluxes. Here, we
report SO2 flux measurements, obtained from a permanent UV camera system,
collected over a two-year-long period spanning two paroxysmal sequences of
Etna’s New South East Crater (NSEC) in December 2020/April 2021 and May/
October 2021. In both cases, SO2 flux increased from ≤ 3250 Mg/day during
“ordinary” activity to ≥ 4200 Mg/day. We interpret these distinct SO2 degassing
regimes in light of seismic and thermal observations and drawing on numerical
simulations of sulfur degassing constrained by parental melt sulfur contents in
Etna’s hawaiites. We find that initiation of a paroxysmal sequence results from
an approximate doubling of the time-averaged rate of magma supply (and
degassing) above the sulfur exsolution level (~150 MPa pressure), to 〉4m3/s.
This corroborates recent models that argue for the triggering of paroxysmal
sequences by escalating supply of volatile-rich magma to a reservoir ~3–4 km
below the summit region. The non-stationary nature of magma flow and volcanic
degassing we identify highlights the need for sustained surveillance to
characterize long-term atmospheric budgets of volcanic volatiles
Description:
Published
Description:
1115111
Description:
OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametrici
Description:
JCR Journal
Keywords:
Etna,
;
volcanic gases
;
SO2 flux
;
paroxysms
;
UV Camera
;
basaltic explosive volcanism
;
04.08. Volcanology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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