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| Titel |
High temporal resolution SO2 flux measurements at Mt. Erebus, Antarctica |
| VerfasserIn |
M. Boichu, C. Oppenheimer  , V. Tsanev, P. R. Kyle |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250024316
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| Zusammenfassung |
| The measurement of SO2 flux from volcanoes is of major importance for monitoring and
hazard assessment purposes, and for evaluation of the environmental impact of volcanic
emissions. We propose here a novel technique for accurate and high time resolution
estimations of the gas flux. This method involves the combination of two wide field of view
UV spectrometers which are capable of collecting, instantaneously, light from cross
sections of the whole gas plume. The two instrument fields of view are separated by a
small angle which enables tracking of inhomogeneities in the gas cloud from which
accurate evaluation of the plume velocity can be made by correlation analysis.
The method has been successfully applied on Mt. Erebus volcano (Antarctica). It
yields rigorous estimations of the plume velocity and gas flux at unprecedented
time resolution (1 Hz) and high accuracy (uncertainty of 25%). During a ~2 h
experiment at Erebus on 26 December 2006, SO2 flux varied between 0.17 and
0.89 ± 0.1 kg s-1 with a vertical plume velocity varying between 1 and 2.5±0.1
m s-1. These measurements provide insight into the short-term variations of the
volcanic degassing of this volcano renowned for its active lava lake. A cyclicity in the
flux, ranging from 11-22 min, is evident and associated to the passive release of
large amounts of gas at the lake surface. Smaller gas puffs, associated with flux
fluctuations on timescales of a few minutes, are also observed intermittently. The
dual-wide field of view DOAS technique promises better integration of geochemical
and geophysical observations and new insights into gas and magma dynamics,
as well as processes of magma storage and gas segregation at active volcanoes. |
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