The Distribution and Origin of Radon, CO2 and SO2 Gases at Arenal Volcano, Costa Rica.
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| Authors: | Williams-Jones, G |
| Year: | 1996 |
| Journal: | M.Sc. Thesis, Université de Montréal 135 |
| Title: | The Distribution and Origin of Radon, CO2 and SO2 Gases at Arenal Volcano, Costa Rica. |
| Committee: Library Theses Search |
Volcanic gases are one of several important indicators used to better understand and forecast volcanic activity. However, direct sampling of these gases is often dangerous or impossible due to the high level of activity and the common inaccessibility of the crater areas of many volcanoes. Indirect methods such as the study of soil gases or the use of remote sensing techniques are thus required. Soil gases such as radon and carbon dioxide have been shown to correlate well with variations in volcanic activity. Similarly, the remote sensing of gases such as sulphur dioxide has proven significant in the geochemical characterisation of both passively and actively degassing volcanoes. Techniques such as these can now provide important clues to the behaviour and future activity of the volcano. This thesis investigates the degassing of Arenal volcano. A small stratovolcano in northwestern Costa Rica, Arenal is one of the most active volcanoes in Central America, having been in continuous eruption since its reactivation in July 1968. Estimates, using petrologic and remote sensing techniques, are made of the quantity of SO2 emitted from Arenal since 1968 and are related to a degassing model for the volcano. Observed spatial and temporal patterns of soil and plume gases are correlated to eruptive and seismic activity, and the origin and transport of these gases at Arenal is discussed. Measurements of seismicity, radon, CO2 and SO2 gas were made as (1) the results could be compared to other volcanoes where similar measurements have been made, (2) it was comparatively simple to measure radon, CO2, and SO2, and (3) these gases are believed to respond to changes in activity and the stress-state of the volcano. |
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