{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Patricia A Nadeau", "hasEmail": "mailto:pnadeau@usgs.gov"}, "description": "Sulfur dioxide (SO2) emission rates are a fundamental measurement for the study and monitoring of active volcanoes. Such emissions inform scientists about the level of volcanic activity or unrest, and they also present a hazard to surrounding populations. Here we present a continuation of a long-term dataset collected by the Hawaiian Volcano Observatory for over four decades using UV spectrometers in below-plume traverses [Casadevall and others, 1987; Elias and others, 1998; Elias and Sutton, 2002; Elias and Sutton, 2007; Elias and Sutton, 2012; Elias and others, 2018a; Elias and others, 2018b; Elias and others, 2020; Kern and others, 2020; Nadeau and others, 2023]. Traverse-based emission rate measurements included herein were compiled between 2023 and 2025 and span six eruptions at K\u012blauea, as well as the quiescent periods between eruptions. No SO2 emission rate measurements were made at other Hawaiian volcanoes (e.g., Mauna Loa) during the timeframe of this data release; only K\u012blauea was emitting SO2 in quantities measurable by UV spectrometer.\nThe dataset begins with measurements obtained during the January 2023 summit eruption of K\u012blauea. SO2 emissions remained elevated as the eruption persisted into March; following the end of the eruption, emissions dropped to background (~100 tonnes/day, or t/d) until the onset of the June 2023 summit eruption. Again, increased SO2 emissions persisted through to the end of the roughly two-week eruption. SO2 emission rates dropped to background once more, and remained low until the September 2023 summit eruption, which lasted only one week. No additional eruptive activity occurred in 2023. In June 2024, however, the first eruption in 50 years on K\u012blauea\u2019s Southwest Rift Zone (SWRZ) took place over the course of approximately nine hours. Unlike most prior eruptions, including those in 2023 included here, SO2 emissions remained elevated for a few days following the end of lava effusion. The next eruption took place over the course of roughly one week in September, on K\u012blauea\u2019s Middle East Rift Zone (MERZ), in and near N\u0101pau Crater. For the duration of the eruption, SO2 emissions varied with the intensity of eruptive activity, but were very low by the end of the eruption and no longer detectable just a few days later. The final portion of this data release covers the December 2024 summit eruption, which, after an initial few days of fissure-based activity, established itself as a prolonged, episodic lava fountain eruption, with pauses on the order of days to weeks between episodes. As such, associated emission rates are variable: all emission rates are above background, but fountaining events emitted tens of thousands of tonnes per day of SO2 while inter-episode emissions were typically over an order of magnitude less. Also adding to the variability of the measured emission rates was the presence of gas pistoning cycles [e.g., Nadeau and others, 2015; Patrick and others, 2016] during many of the pauses from mid-March 2025 onward.\nIn this data release, we include raw spectra collected by ultraviolet (UV) spectrometers on traverses beneath SO2 plumes, derived SO2 emission rates and associated metadata for each individual traverse, and means of SO2 emission rates for each separate traverse campaign/set of traverses. Data are separated by the three eruption sites/degassing locations: K\u012blauea summit (Halema\u02bbuma\u02bbu), K\u012blauea MERZ (N\u0101pau Crater), and K\u012blauea SWRZ.\nReferences\nCasadevall, TJ., Stokes, J.B., Greenland, L.P., Malinconico, L.L., Casadevall, J.R., and Furukawa, B.T. (1987). SO2 and CO2 emission rates at Kilauea Volcano, 1979-1984, chap. 29 in Decker, R.W., Wright, T.L., and Stauffer, P.H., eds., Volcanism in Hawaii: U.S. Geological Survey Professional Paper 1350, v. 1, p. 771-780.\nElias, T., and Sutton, A. J. (2002). Sulfur Dioxide Emission Rates of K\u012blauea Volcano, Hawai\u2018i, an Update: 1998\u20132001. U.S. Geological Survey Open-File Report 02\u2013460, 29. Available at: https://pubs.usgs.gov/of/2002/of02-460/\nElias, T., and Sutton, A. J. (2007). Sulfur Dioxide Emission Rates from K\u012blauea Volcano, Hawai\u2018i, an Update: 2002\u20132006. U.S. Geological Survey Open-File Report 2007\u20131114, Version 1.0, 37. Available at: https://pubs.usgs.gov/of/2007/1114/\nElias, T., and Sutton, A. J. (2012). Sulfur Dioxide Emission Rates from K\u012blauea Volcano, Hawai\u2018i, 2007\u20132010. U.S. Geological Survey Open-File Report 2012\u20131107, 25. Available at: https://pubs.usgs.gov/of/2012/1107/\nElias, T., Sutton, A. J., Stokes, J.B., Casadevall, T.J. (1998). Sulfur Dioxide Emission Rates of K\u012blauea Volcano, Hawai\u2018i, 1979-1997. U.S. Geological Survey Open-File Report 98-462 Version 1.0. Available at: https://pubs.usgs.gov/of/1998/of98-462/\nElias, T., Kern, C., Horton, K., Garbeil, H., and Sutton, A.J. (2018a). SO2 emission rates from Kilauea Volcano, Hawaii (2014-2017): U.S. Geological Survey data release, https://doi.org/10.5066/F7794402\nElias, T., Kern, C., Horton, K. A., Sutton, A. J., & Garbeil, H. (2018b). Measuring SO2 Emission Rates at K\u012blauea Volcano, Hawaii, Using an Array of Upward-Looking UV Spectrometers, 2014\u20132017. Frontiers in Earth Science, 6(214). https://doi.org/10.3389/feart.2018.00214\nElias, T., Kern, C., Sutton, A.J., and Horton, K. (2020). Sulfur dioxide emission rates from K\u012blauea Volcano, Hawaii, 2008-2013: U.S. Geological Survey data release, https://doi.org/10.5066/P9K0EZII\nKern, C., Lerner, A. H., Elias, T., Nadeau, P. A., Holland, L., Kelly, P. J., Werner, C. A., Clor, L. E., & Cappos, M. (2020). Quantifying gas emissions associated with the 2018 rift eruption of K\u012blauea Volcano using ground-based DOAS measurements. Bulletin of Volcanology, 82(7), 55. https://doi.org/10.1007/s00445-020-01390-8\nNadeau, P.A., Werner, C.A., Waite, G.P., Carn, S.A., Brewer, I.D., Elias, T., Sutton, A.J., and Kern, C. (2015). Using SO2 camera imagery and seismicity to examine degassing and gas accumulation at K\u012blauea Volcano, May 2010. Journal of Volcanology and Geothermal Research, 300, 70-80. https://doi.org/10.1016/j.jvolgeores.2014.12.005\nNadeau, P.A., Kern, C., Cappos, M.J., Elias, T., Warren, S.M., Lerner, A.H., Sealing, C.R., Slagle, C.L., Moisseeva, N., Holland, L.D., Clor, L., and Werner, C.A. (2023). Sulfur dioxide emission rates from Hawaiian volcanoes, 2018-2022: U.S. Geological Survey data release, https://doi.org/10.5066/P9SNW2B7.\nPatrick, M.R., Orr, T., Sutton, A.J., Lev, E., Thelen, W., and Fee, D. (2016). Shallowly driven fluctuations in lava lake outgassing (gas pistoning), K\u012blauea Volcano. Earth and Planetary Science Letters, 433, 326-338. https://doi.org/10.1016/j.epsl.2015.10.052", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P1N2DWRY", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.698fc90db66b01ea6aa36728.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_698fc90db66b01ea6aa36728", "keyword": ["DOAS", "Hawaii", "K\u012blauea", "SO2 emission rate", "Spectroscopy", "Sulfur dioxide", "USGS:698fc90db66b01ea6aa36728", "Volcano", "geoscientificInformation", "volcanology"], "modified": "2026-03-05T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-155.3584, 19.2807, -155.1167, 19.4465", "theme": ["geospatial"], "title": "Traverse-based sulfur dioxide emission rates from Hawaiian volcanoes, 2023\u20132025"}