Magma composition, eruptive frequency, and tectonic context are highly variable features of volcanoes. Within such contexts, volcanic volatiles play a key role in magma transport, and impact on the style and timing of volcanic eruptions. Gas chemical and isotopic compositions may change over time, reflecting variations in the magmatic feeding systems of volcanoes. As the magma rises from depth, the decreasing pressure allows volatile species to partition into the gas phase. Bubbles form, grow, and coalesce, and gases start to flow through the vesciculated magma. Eventually, fluid and gases reach the surface and are released into the atmosphere through soil degassing, fumarolic vents, or bubbling through a water surface, forming large plumes or explosive eruption columns.
Volcanic emissions can also have significant impacts on the terrestrial environment, atmospheric composition, climate, and human health at various temporal and spatial scales. For instance, sulfur dioxide emissions can cause acid rain and influence aerosol formation, and if an eruption column reaches the stratosphere, it causes global dimming and a lowering of the Earth’s surface temperatures that may last for years. Similarly, halogens can dramatically affect proximal ecosystems, influence the oxidation capacity of the troposphere, and alter the stratospheric ozone layer.
Understanding the physicochemical processes underlying volcanic eruptions has improved tremendously through major advances in computational and analytical capabilities, instrumentation and monitoring networks, thereby improving the ability to reduce volcanic hazards. This session focuses on all aspects of volcanic volatile degassing in the Earth’s system through case studies and theoretical and multidisciplinary approaches. 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 at local and global scales.
Finally, but significantly, we strongly encourage critical contributions that offer alternative explanations and viewpoints, willingness to consider new ideas supported by evidence, and with the potential to improve the ability to forecast eruptions.