Publication Date:
2022-05-06
Description:
Water vapour (H2O) is the dominant species in volcanic gas plumes. Therefore,measurements of
H2O fluxes could provide valuable constraints on subsurface degassing and magmatic processes.
However, due to the large and variable concentration of this species in the background atmosphere,
little attention has been devoted to monitoring the emission rates of this species from volcanoes.
Instead, the focus has been placed on remote measurements of SO2, which is present in far lower
abundances in plumes, and therefore provides poorer single flux proxies for overall degassing conditions.
Here, we present a new technique for the measurement of H2O emissions at degassing volcanoes at
high temporal resolution ( 1 Hz), via remote sensing with low cost digital cameras. This approach
is analogous to the use of dual band ultraviolet (UV) cameras for measurements of volcanic SO2
release, but is focused on near infrared absorption by H2O. We report on the field deployment of
these devices on La Fossa crater, Vulcano Island, and the North East Crater of Mt. Etna, during which
in-plume calibration was performed using a humidity sensor, resulting in estimated mean H2O fluxes
of 15 kg s1 and 34 kg s1, respectively, in accordance with previously reported literature values.
By combining the Etna data with parallel UV camera and Multi-GAS observations, we also derived,
for the first time, a combined record of 1 Hz gas fluxes for the three most abundant volcanic gas
species: H2O, CO2, and SO2. Spectral analysis of the Etna data revealed oscillations in the passive
emissions of all three species, with periods spanning 40–175 s, and a strong degree of correlation
between the periodicity manifested in the SO2 and H2O data, potentially related to the similar
exsolution depths of these two gases. In contrast, there was a poorer linkage between oscillations in
these species and those of CO2, possibly due to the deeper exsolution of carbon dioxide, giving rise
to distinct periodic degassing behaviour.
Description:
Published
Description:
Article 146
Description:
5V. Dinamica dei processi eruttivi e post-eruttivi
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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