A. Jeff Sutton

Observing and Forecasting Vog Dispersion from Kīlauea Volcano, Hawaii

AbstractEmissions from Kīlauea volcano, known locally as “vog” for volcanic smog, pose significant environmental and health risks to the Hawaiian community. The Vog Measurement and Prediction (VMAP) project was conceived to help mitigate the negative impacts of Kīlauea’s emissions. To date, the VMAP project has achieved the following milestones: i) created a custom application of the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT, hereafter Vog model) to produce statewide forecasts of the concentration and dispersion of sulfur dioxide (SO2) and sulfate aerosol from Kīlauea volcano; ii) developed an ultraviolet (UV) spectrometer array to provide near-real-time volcanic gas emission rate measurements for use as input into the Vog model; iii) developed and deployed a stationary array of ambient SO2 and meteorological sensors to record the spatial characteristics of Kīlauea’s gas plume in high temporal and spatial resolution for model verification; and iv) developed web-based tools to ...

Influence of eruptive style on volcanic gas emission chemistry and temperature

Gas bubbles form as magmas ascend in the crust and exsolve volatiles. These bubbles evolve chemically and physically as magma decompression and crystallization proceed. It is generally assumed that the gas remains in thermal equilibrium with the melt but the relationship between gas and melt redox state is debated. Here, using absorption spectroscopy, we report the composition of gases emitted from the lava lake of Kīlauea Volcano, Hawaii, and calculate equilibrium conditions for the gas emissions. Our observations span a transition between more and less vigorous-degassing regimes. They reveal a temperature range of up to 250 °C, and progressive oxidation of the gas, relative to solid rock buffers, with decreasing gas temperature. We suggest that these phenomena are the result of changing gas bubble size. We find that even for more viscous magmas, fast-rising bubbles can cool adiabatically, and lose the redox signature of their associated melts. This process can result in rapid changes in the abundances of redox-sensitive gas species. Gas composition is monitored at many volcanoes in support of hazard assessment but time averaging of observations can mask such variability arising from the dynamics of degassing. In addition, the observed redox decoupling between gas and melt calls for caution in using lava chemistry to infer the composition of associated volcanic gases.The redox state of volcanic gases and melts can become decoupled during magma ascent, according to observations of gas emissions from Kīlauea’s lava lake, Hawaii. Cooling of fast-rising bubbles changes the abundance of redox-sensitive gas species.