Publication Date:
2017-04-04
Description:
Here we report results from a multidisciplinary field campaign at Villarrica volcano, Chile, in March 2009. A
range of direct sampling and remote sensing techniqueswas employed to assess gas and aerosol emissions from
the volcano, and extend the time series of measurements that have been made during recent years. Airborne
traverses beneath the plume with an ultraviolet spectrometer yielded an average SO2 flux of 3.7 kg s−1. This
value is similar to previous measurements made at Villarrica during periods of quiescent activity. The
composition of the plume was measured at the crater rim using electrochemical sensors and, for the first time,
open-path Fourier transforminfrared spectroscopy, yielding a composition of 90.5 mol% H2O, 5.7% CO2, 2.6%SO2,
0.9% HCl, 0.3% HF and b0.01% H2S. Comparison with previous gas measurements made between 2000 and 2004
shows a correlation between increased SO2/HCl ratios and periods of increased activity. Base-treated filter packs
were also employed during our campaign, yielding molar ratios of HBr/SO2=1.1×10−4, HI/SO2=1.4×10−5
and HNO3/SO2=1.1×10−3 in the gas phase. Our data represent the most comprehensive gas inventory at
Villarrica to date, and the first evaluation of HBr and HI emissions from a South American volcano. Sun
photometry of the plume showed the near-source aerosol size distributions were bimodal with maxima at b0.1
and ~1 μm. These findings are consistent with results from analyses in 2003. Electron microscope analysis of
particulatematter collected on filters showed an abundance of sphericalmicron-sized particles that are rich in Si,
Mg and Al. Non-spherical, S-rich particles were also observed.
Description:
Antofagasta plc via the University of
Cambridge Centre for Latin American Studies, NERC Field Spectroscopy Facility, NERC projectNE/F004222/1, “Volgaspec” projectANR-06-CATT-012-01 and from the NOVAC project. Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento di
Protezione Civile-Regione Sicilia. Christ's
College, University of Cambridge,
NERC IKIMP project, (NE/G001219/1) and NERC grantNE/G01700X/1 for financial support. NERC National Centre for EarthObservation (“Dynamic Earth and geohazards”)
Description:
Published
Description:
62-75
Description:
1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
Description:
JCR Journal
Description:
reserved
Keywords:
Villarrica
;
FTIR
;
SO2 flux
;
DOAS
;
04. Solid Earth::04.08. Volcanology::04.08.01. Gases
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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