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UV-Spectroscopic Volcanic Emission Measurements: Potential Promise and Lingering Challenges: Christoph Kern
Project Title: UV-Spectroscopic Volcanic Emission Measurements: Potential Promise and Lingering Challenges
Mendenhall Fellow: Christoph Kern, (360) 993-8922, ckern@usgs.gov
Duty Station: Vancouver, Washington
Start Date: October 4, 2010
Education: Ph.D. (Physics), University of Heidelberg, Heidelberg, Germany, 2009
Research Advisor: Cynthia Werner, (360) 993-8980, cwerner@usgs.gov; Jeff Sutton, (808) 967-8805, ajsutton@usgs.gov; Ulrich Platt, University of Heidelberg, uplatt@iup.uni-heidelberg.de
      Christoph Kern

Project Description: In recent years, the measurement of volcanic gas emissions has gained importance in volcanology.  The improved understanding of  gas release processes has led to an increased interest in volatile emission fluxes, gas speciation, and atmospheric plume evolution as parameters providing information about volcanic systems. Volcanic gas emission fluxes have been shown to provide information on the magnitude of erupted or degassed magma in certain systems (see, for example, Delgado and others, 2001), while the speciation of gases emitted from a volcano at a given time can provide insights into degassing conditions such as pressure or depth for example, Burton and others, 2007). Aiuppa and others (2007) showed that such information is extremely useful and may even allow the prediction of imminent eruptions. Finally, the evolution of volcanic plumes after being emitted into the atmosphere is also of great interest because volcanic emissions can be hazardous to vegetation, animals, and humans, as well as influencing atmospheric chemistry on local and global scales (for example, von Glasow and others, 2008).

The groundbreaking results of studies such as those mentioned above have driven the continuous development of remote sensing instruments and their application in volcanic environments. The correlation spectrometer (COSPEC) (see, for example, Moffat and Millán, 1971), differential optical absorption spectrometers (DOAS) (for example, Platt and Stutz, 2008; Kern 2009), Fourier transform infrared spectrometers (FTIR) (for example, Mori and others, 1993), and most recently the SO2 camera (for example, Mori and Burton, 2006; Kern and others, 2010a) have made possible the continuous monitoring of volcanic gas emissions at high spatial and temporal resolutions. This Mendenhall research project is focused on applying spectroscopic techniques in the ultra-violet wavelength region to measure volcanic gas emission fluxes and plume compositions.

One issue being addressed is the implementation of advanced data analysis tools for improving our understanding of atmospheric radiative transfer in and around volcanic plumes. Knowledge about optical path distributions between the sun and a remote sensing instrument is crucial for deriving accurate gas flux and composition values (Kern and others, 2010b). Next, accurate, long-term continuous degassing data sets are being compiled from Kilauea volcano (Hawaii) and other volcanoes around the world, and possible links between degassing and other geophysical parameters (for example, seismicity, deformation, temperature) are being evaluated. Also, the chemical and physical evolution of volcanic plumes in Hawaii and Alaska is being examined. Of special interest is the so-called “bromine explosion” mechanism, which rapidly converts bromine captured in volcanic aerosols and reservoir species to highly reactive gaseous bromine species such as BrO (see for example, Bobrowski and others, 2003; Kern and others, 2009). A quantitative description of this process is necessary to link measured BrO to the primary emitted volcanic bromine amount, which might then be used as an indicator for shallow magma degassing.

The underlying question to be addressed by the project is, therefore, “How is volcanic degassing behavior linked to actual geophysical processes?” In other words, what can volcanic gases tell us about processes occurring deep below the Earth’s surface? With a better understanding of these processes, continuously monitored volcanic gas emissions can be used as an independent parameter for volcanic risk assessment and may provide warning of future eruptions.

References
Aiuppa, A., Moretti, R., Federico, C., Gaetano, G., Gurrieri, S., Liuzzo, M., Papale, P., Shinohara, H., and Valenza, M., 2007, Forecasting Etna eruptions by real-time observation of volcanic gas composition: Geology, v. 35, p. 1115–1118.

Bobrowski , N., Hönninger, G., Galle, B., and Platt, U., 2003, Detection of bromine monoxide in a volcanic plume: Nature, v. 423, p. 273–276.

Burton, M.R., Allard, P., Murè, F., and La Spina, A., 2007, Magmatic gas composition reveals the source depth of slug-driven Strombolian explosive activity: Science, v. 317, p. 227–230.

Delgado Granados, H., Cárdenas González, L., and Piedad Sánchez, N., 2001, Sulfur dioxide emissions from Popocatépetl volcano (Mexico): Case study of a high-emission rate, passively degassing erupting volcano: Journal of Volcanological and Geothermal Research, v. 108, p. 107–120.

Kern, C., 2009, Spectroscopic measurements of volcanic gas emissions in the ultra-violet wavelength region: Heidelberg, University of Heidelberg, Ph.D. thesis,
http://www.ub.uni-heidelberg.de/archiv/9574.

Kern, C., Sihler, H., Vogel, L., Rivera, C., Herrera, M., and Platt, U., 2009, Halogen oxide measurements at Masaya volcano, Nicaragua using active long path differential optical absorption spectroscopy: Bulletin of Volcanology, v. 71, p. 659–670, doi:10.1007/s00445-008-0252-8.

Kern, C., Kick, F., Lübcke, P., Vogel, L., Wöhrbach, M., and Platt, U., 2010a, Theoretical description of functionality, applications, and limitations of SO2 cameras for the remote sensing of volcanic plumes: Atmospheric Measurement Techniques, v. 3, p. 733–749, doi:10.5194/amt-3-733-2010.

Kern, C., Deutschmann, T., Vogel, L., Wöhrbach, M., Wagner, T., and Platt, U., 2010b, Radiative transfer corrections for accurate spectroscopic measurements of volcanic gas emissions: Bulletin of Volcanology, v. 72, p. 233–247, DOI:10.1007/s00445-009-0313-7.

Moffat, A.J., and Millán, M.M., 1971, The applications of optical correlation techniques to the remote sensing of SO2 plumes using sky light: Atmosperic Environment, v. 5, p. 677–690.

Mori , T., Notsu, K., Tohjima, Y., and Wakita, H., 1993, Remote detection of HCl and SO2 in volcanic gas from Unzen Volcano, Japan: Geophysical Research Letters, v. 20, p. 1355–1358.

Mori , T., and  Burton, M.R., 2006, The SO2 camera: A simple, fast and cheap method for ground-based imaging of SO2 in volcanic plumes: Geophysical Research Letters, v. 33, p. L24804. doi:10.1029/2006GL027916.

Platt, U., and  Stutz, J., 2008, Differential Optical Absorption Spectroscopy—Principles and applications: Berlin Heidelberg New York, Springer.

von Glasow, R., Bobrowski, N., and Kern, C., 2008, The effects of volcanic eruptions on atmospheric chemistry: Chemical Geology, v. 263, p. 131–142.
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