As magma rises from depth, decreasing pressure allows volatile species to partition to the gas phase. Bubbles form, grow, coalesce and gases start to flow through vesiculated magma. Eventually, gases reach the surface and are released into the atmosphere, in some cases diffused through a soil or bubbling through a water pool, in other cases forming large plumes or explosive eruption columns.
Volcanic volatiles play a key role in magma transport and have significant impact on the style and timing of volcanic eruptions. Gas composition and flux may change with time, reflecting variations in the magmatic feeding system of volcanoes. Measuring volcanic gases therefore constitutes a powerful tool for monitoring and understanding active volcanoes.
Volcanic emissions can also have profound impacts on terrestrial environment, atmospheric composition, climate and human health at various temporal and spatial scales. For instance, sulfur dioxide emissions can cause acid rain, influence aerosol formation and, if an eruption column reaches the stratosphere, cause global dimming and a decrease in Earth’s surface temperatures for years. Similarly, halogens can dramatically impact proximal ecosystems, influence the oxidation capacity of the troposphere and alter the stratospheric ozone layer.
This session will focus on all aspects of volcanic volatile degassing in the Earth’s system. We invite contributions discussing how novel measurement techniques, field measurements, direct and remote ground- and space-based observations and modeling studies of volcanic degassing can provide new insights into volcanic and atmospheric processes on local and global scales. Studies with the potential to improve our ability to forecast eruptions are specifically encouraged.