Publication Date:
2020-10-13
Description:
Since 1999, Mount Etna’s (Italy) South-East crater
system has been characterised by episodic lava fountaining.
Each episode is characterised by initial strombolian activity
followed by transition to sustained fountaining to feed higheffusion
rate lava flow. Here, we use thermal infrared data
recorded by a permanent radiometer station to characterise
the transition to sustained fountaining fed by the New
South-East crater that developed on the eastern flank of the
South-East crater starting from January 2011. We cover eight
fountaining episodes that occurred between 2012 and 2013.
We first developed a routine to characterise event waveforms
apparent in the precursory, strombolian phase. This allowed
extraction of a database for thermal energy and waveform
shape for 1934 events. We detected between 66 and 650
events per episode, with event durations being between 4
and 55 s. In total, 1508 (78 %) of the events had short waxing
phases and dominant waning phases. Event frequency increased
as climax was approached. Events had energies of
between 3.0× 106 and 5.8× 109 J, with rank order analysis
indicating the highest possible event energy of 8.1× 109 J.
To visualise the temporal evolution of retrieved parameters
during the precursory phase, we applied a dimensionality reduction
technique. Results show that weaker events occur
during an onset period that forms a low-energy Bsink^. The
transition towards fountaining occurs at 107 J, where subsequent
events have a temporal trend towards the highest energies,
and where sustained fountaining occurs when energies
exceed 109 J. Such an energy-based framework allows researchers
to track the evolution of fountaining episodes and
to predict the time at which sustained fountaining will begin.
Description:
Published
Description:
15
Description:
3V. Dinamiche e scenari eruttivi
Description:
JCR Journal
Description:
restricted
Keywords:
Mount Etna . Strombolian events . Lava fountaining . Explosive regime transition . Radiometry
;
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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