Collecting Volcanic Gas Samples

Steven Ingebritsen (lower right, in blue hat) kneels in the warm mud as he collects samples of the gases emitted from the fumaroles on the north side of Crater Rock on Mount Hood. The samples are taken back to the laboratory for an analysis of the gases' chemical composition. By routinely collecting gas samples and comparing their composition to past measurements, scientists can track the geochemical evolution of the volcanic system and become aware of any subtle changes that might indicate a rekindling of eruptive activity. Although Mount Hood is not currently in a state of eruption, it remains an active volcano.