Volcano Watch: Mapping Kilauea’s Gas Emissions

  • USGS photo by K. Mulliken Two HVO scientists traverse the down-dropped block of Kilauea’s caldera with MultiGAS instruments for measuring volcanic gases on July 22. Rising gases interact with and alter surrounding rocks, resulting in the light-colored ground the scientists are walking on.

Large quantities of volcanic gases, such as carbon dioxide (CO2), sulfur dioxide (SO2), and hydrogen sulfide (H2S), are released into the atmosphere during volcanic eruptions. But even between eruptions, smaller amounts of the same gases continue to escape and can provide important clues about the current state of the volcano and the underlying magma. But to measure them, you first must identify where gas is coming from.