Publication Date:
2024-04-05
Description:
This chapter reviews the geochemical and
isotopic data from the fumarolic gas discharges
collected in a discontinuous mode from 1998 to
2014 at Poás volcano. During this period, the
“Tico” volcano experienced a renewed phreatic
activity that started in 2006 after a couple of
decades of relative quiescence. In January
2009, a 6.2 Mw earthquake hit the village of
Cinchona, which is located a 4 km to the east
of Poás. As the phreatic activity kept evolving,
the hyperacidic lake (“Laguna Caliente”) dried
out and the high-temperature fumaroles that
previously were likely entering the lake were
revealed, though not accessible. The pyroclastic
dome that formed in the early fifties was
destroyed at the beginning of 2017 by several
relatively small phreatomagmatic (strombolian
and vulcanian type) small-size eruptions. The
risk of sudden phreatic and phreato-magmatic
events prevented the direct sampling of the
fumaroles and as a consequence, no geochemical
data were sampled in the last three years.
Nevertheless, interesting hints were recorded
by the gas geochemistry before the 2006
phreatic activity and the 2009 Cinchona seismic
events, mainly based on the temporal
variations of the H2S/SO2, H2/H2O, H2/Ar,
CO/CO2, CH4/CO2 and HCl/HF ratios. However,
in most cases the geochemical record is
not complete since the gas discharging vents
migrated or stopped their activity and new
fumaroles formed up to the recent visual
observations.
Description:
Published
Description:
235–260
Description:
OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametrici
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
book chapter
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