Electron probe microanalytical data of minerals and glass from rock samples from Pavlof Volcano, Alaska, Raw Data File 2022-7, presents electron microprobe analytical data from minerals from lava samples collected at Pavlof Volcano by Alaska Volcano Observatory (AVO) geologist Jessica Larsen during fieldwork in 2017 and from tephra samples described in Waythomas and others (2017). Samples include those produced during recent eruptions of Pavlof in 1986, 1996, 2007, 2013, 2014, and 2016. Pavlof Volcano is an undissected stratovolcano located approximately 58 km northeast of Cold Bay, in the southwestern portion of the Alaska Peninsula. Electron probe micro-analysis (EPMA) data are reported from the major mineral phases: orthopyroxene, clinopyroxene, olivine, plagioclase, and magnetite. Sample descriptions, locations, and types are included in the metadata associated with the analytical data table. The data are available from the DGGS website: http://doi.org/10.14509/30854.

Glass laser ablation-inductively coupled plasma-mass spectrometry analysis methods, precision, and accuracy data for tephra studies in Alaska, Techniques and Methods 1, reports the analytical conditions, standard reference material (SRM) results, and preferred post-processing methodologies for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) measurements supporting tephra studies in Alaska between 2018 and 2024. We evaluate the long-term accuracy and precision of our methodologies by comparing our calculated SRM concentrations to the Geological and Environmental Reference Materials database (GeoReM) preferred concentration values for the following SRMs: BCR-2G, BHVO-2G, ATHO-G, NIST-612, GSD-1G, and GSE-1G. We show that our LA-ICP-MS methodologies produce accurate and consistent measurements across numerous analytical sessions, even when instrumentation changed. Overall, these results indicate that Alaska tephra matrix glass measurements, like SRM measurements, are accurate, precise, and comparable between analytical sessions. These data and report are available from the DGGS website: http://doi.org/10.14509/31471.

This Raw Data File presents major-oxide glass geochemical results from the ca. 3.6 ka caldera-forming eruption of Aniakchak volcano, Alaska. These data are part of a larger effort to identify and characterize tephra deposits from the largest eruptions in Alaska for use as geochronological marker horizons. Aniakchak is one of at least 29 volcanoes in Alaska that has had multiple large tephra-producing eruptions. Other deposit and sample metadata including geospatial distributions of this tephra deposit are held in the Alaska Volcano Observatory's online database, the Geologic Database of Information on Volcanoes in Alaska (GeoDIVA), and will be linked to these new geochemical data once published. Products included in this data release are background information on the larger project, methods of sample collection, processing, analysis, and data reduction spreadsheets showing 1) raw point major-oxide data, 2) normalized and averaged major-oxide data, and 3) basic sample metadata. Users can access the complete report and digital data from the DGGS website: http://doi.org/10.14509/29777 and from the Alaska Volcano Observatory's online database, the Geologic Database of Information on Volcanoes in Alaska (GeoDIVA)

Alaska Volcano Observatory (AVO) geologists from the U.S. Geological Survey (USGS) and the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted fieldwork at Mount Veniaminof during field excursions between 2001 and 2016. The primary purpose of the fieldwork was geologic investigation of Veniaminof volcano to elucidate its eruptive history and understand its eruptive behavior. Teams of geologists focused on 1) edifice lava flows, 2) flowage deposits (lahars and pyroclastic flows), and 3) tephra-fall deposits. This Raw Data File comprises 61 whole-rock analyses of pumices from Holocene-age tephra deposits collected from 36 field stations on the flanks of Veniaminof volcano in 2001-2004, 2010, and 2016. All but four samples in this report were collected by geologists Kristi Wallace and Chris Waythomas during 1- to 2-week summer fieldwork campaigns. Thomas Miller and Charles Bacon contributed four pumice samples of a young dacite-composition tephra collected in 2001 and 2002. Mount Veniaminof is an ice-clad, basalt-to-dacite stratovolcano topped by an ice-filled caldera 10 km (about 6 mi) in diameter, located 775 km (482 mi) southwest of Anchorage on the Alaska Peninsula. With a volume of approximately 350 km3 (approximately 84 mi3) Veniaminof is one of the largest and most active volcanoes of the Aleutian Arc. Two Holocene caldera-forming eruptions are recorded in extensive pyroclastic-flow deposits around the volcano. Veniaminof has had at least 15 eruptions in the past 200 years, all from the approximately 300-m-high (about 984-ft-high) intracaldera cone and all largely basaltic-basaltic andesite composition, producing small lava flows and minor tephra deposits mostly confined to the caldera boundaries. The most recent explosive eruption was in 2018. Geochemical characterization of tephra deposits is most commonly executed by using glass-phase chemistry rather than whole-rock (bulk) geochemistry. The bulk composition of a tephra may change over fallout distance by eolian fractionation and therefore cannot be used to correlate tephra deposits over long distances. Whole-rock composition is commonly used to characterize juvenile material from flowage deposits (lahars and pyroclastic flows) and lavas. In order to readily compare (correlate) juvenile material from proximal tephra-fall deposits with other proximal deposits, tephra whole-rock analysis is required. This Raw Data File is focused only on whole-rock geochemical analyses of significant coarse-grained tephra deposits exposed on the flanks of Veniaminof volcano for use in correlating tephra deposits across the large volcanic edifice, and with proximal flowage deposits and edifice lava flows. Results of glass geochemistry of Veniaminof tephra and all other whole-rock analyses of samples collected is part of an ongoing study and not included in this report. Files can also be downloaded from the DGGS website (http://doi.org/10.14509/30578) and is also available in .html and .csv from the AVO Geochemical Database (https://avo.alaska.edu/geochem). Sample descriptions, locations, and sample types are included in the analytical data table. Samples collected during this project, including hand sample material, remaining powder from these whole-rock analyses, and partially crushed sample remains are stored at the Alaska Geologic Materials Center or at the USGS Alaska Tephra Laboratory in Anchorage.

Tephra samples and analyses from the 2018-2023 eruption of Semisopochnoi Volcano, Alaska, Raw Data File 2025-15, includes samples and analyses collected from the 2018-2023 eruption of Semisopochnoi volcano in the western Aleutian Islands, Alaska. Samples were collected during two field visits: May 30 to June 1, 2021, and June 10, 2023. A total of sixteen samples were collected across Semisopochnoi Island at varying distances from the eruption source, the north crater of Mount Young. Samples were collected from the surface on snow, grass, or other substrates that suggested deposition during recent eruptive activity but are, in all cases, aggregates of prior eruption events up to the sample date and may contain minor wind-blown contamination from older surfaces. These data and report are available from the DGGS website: http://doi.org/10.14509/31645 and a subset of the results are archived in the Geologic Database of Information on Volcanoes in Alaska (GeoDIVA; Cameron and others, 2022, doi.org/10.14509/geodiva).

Tephra samples and analyses from Cook Inlet source volcanoes and Anchor Point, Alaska, Raw Data File 2023-25, proivides samples and analyses collected from source volcanoes of the Cook Inlet region, Alaska, including Hayes Volcano, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Mount Douglas, Fourpeaked Mountain, and Kaguyak Crater. The report also includes tephra and soil samples and analyses from a stratigraphic section examined near Anchor Point, Alaska. These samples were collected over many years during geologic investigations of the eruptive histories for these source volcanoes, and in regional studies of eruption impacts, and are compiled here to support research characterizing the composition and impacts of these volcanoes on the Cook Inlet region. The analytical data tables associated with this report are provided in digital format as comma-separated value (CSV) files. They are available from the DGGS website: http://doi.org/10.14509/31090 and are archived in the Geologic Database of Information on Volcanoes in Alaska (GeoDIVA; Cameron and others, 2022, doi.org/10.14509/geodiva).

During the summers of 2017 and 2018, Alaska Volcano Observatory (AVO) geologists from the University of Alaska, Fairbanks (UAF), the U.S. Geological Survey (USGS), and the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted fieldwork at Pavlof Volcano (55.4173 N, -161.8937 W), on the Alaska Peninsula, Alaska. The fieldwork was conducted in support of geologic mapping and tephrostratigraphy, to improve the documentation of recent Pavlof eruptions, and to better assess hazards associated with Pavlof eruptions. As a result, samples of lava and various pyroclasts (mainly bombs and lapilli) were collected for whole rock geochemistry analyses. This report includes whole rock major- and trace-element data from lava and bomb samples from the 1996, 2013, 2014, and 2016 eruptions, along with samples of lava and lapilli fall deposits, presumed to be of Holocene age, collected from outcrops around Pavlof and Pavlof Sister volcanoes. We also include electron probe microanalyzer (EPMA) data from tephra glass samples from the 1986 (AT-2822), 1996 (AT-2823), 2007 (AT-2824), and 2013 (AT-2821) eruptions. These samples were initially analyzed at the USGS office in Menlo Park and were re-analyzed for this report in the Advanced Instrumentation Laboratory (AIL) at UAF for comparison. Tephra EPMA glass data from the 2016 eruption, analyzed in the AIL, is also included from sample AT-3680. The analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files. Users can access the complete report and digital data from the DGGS website: http://doi.org/10.14509/30580.