Geophysical gas monitoring using optical techniques: volcanoes, geothermal fields and mines

摘要

Optical spectroscopy provides powerful means for studying geophysical gas emissions. An extensive research program in this field has been performed by Swedish researchers in collaboration with European partners during the last 10 years, and a review of the activities and results is given. The techniques suitable for geophysical gas monitoring include the differential absorption lidar (DIAL), differential optical absorption speetroscopy (DOAS), diode laser spectroscopy and gas correlation imaging. Field experiments regarding atomic mercury emissions from geothermal fields were performed with a mobile lidar laboratory in Iceland and in Italy. The atomic mercury concentrations and fluxes from mercury mines were also determined at Abbadia S. Salvatore (Italy) and Almaden (Spain). The volcanic emissions of sulfur dioxide were studied in four ship-borne campaigns concerning the three Italian volcanoes Mt. Etna, Stromboli and Vulcano. Comparisons between the results from the DIAL and passive techniques (DOAS and correlation spectroscopy) were performed. Infrared spectroscopy for geophysical applications is now being developed and will also be discussed.