{"action":"create","ckan_id":null,"date_created":"Sat, 21 Feb 2026 21:11:16 GMT","date_finished":null,"harvest_job_id":"fb591ca5-43f4-4ca4-a149-94fd73e2a6d1","harvest_source_id":"31f41541-38a0-400b-b240-10ebcb0acd9a","id":"5fd674a2-59b3-4a0d-b3d3-f5064bebcfb4","identifier":"https://dggs.alaska.gov/webpubs/metadata/RI2023-1.xml","parent_identifier":null,"source_hash":"1159a70cd674adc0ea6ccafa97f2be8f3fd60cfc71f4fcc20202e318cb1edf3b","source_raw":"Larsen, J.F.Neal, C.A.Schaefer, J.R.Nye, C.J.2023Geologic map of Okmok VolcanogeodatabaseReport of InvestigationRI 2023-1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys63 p., 4 sheetshttps://doi.org/10.14509/31015Geologic map of Okmok Volcano, Report of Investigation 2023-1, shows the distribution of historic, Holocene, and late Pleistocene volcanic rocks and deposits related to Okmok Volcano. Okmok Volcano is one of 54 historically active volcanoes in the Alaska-Aleutian volcanic arc that stretches across southern mainland Alaska and the Aleutian Islands. Okmok Volcano dominates the northeastern portion of Umnak Island, which is 100 km southwest of Unalaska/Dutch Harbor and 1,400 km southwest of Anchorage. Okmok Volcano is one of the most frequently active volcanoes in the Aleutian volcanic arc. In 1998, the Alaska Volcano Observatory (AVO) began a multi-year effort to expand geophysical monitoring in the central Aleutians Islands, including at Okmok Volcano. These data support the development of a modern geologic map of Okmok Volcano and related investigation of its eruptive history and hazards. The complete report, geodatabase, and ESRI fonts and style files are available from the DGGS website: http://doi.org/10.14509/31015.This data describes the nature and character of samples from a past eruption to aid in the discussion of spatial and temporal patterns of Alaska volcanism. In addition, the work supports improvements to eruption scenario forecasts and hazard response.This geodatabase is organized according to the AK GeMS mapping schema Hendricks, M.D., Ekberg, P.G., Athey, J.E., Wyatt, W.C., Willingham, A.L., and Naibert, T.J., 2021, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 170, 10 p. https://doi.org/10.14509/30669. The distribution package includes ESRI fonts and style files, along with usage instructions. Further documentation of the symbology is provided by Ekberg, P.G., Hendricks, M.D., and Athey, J.E., 2021, AK GeMS symbology: A description of the AK GeMS style file: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 169, 7 p. https://doi.org/10.14509/3058419832023ground conditionCompleteNone planned-168.441430-167.77998253.57644953.221880ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical Surveys40Ar/39ArAshfallCalderaDGGSFumarole ChemistryGeMS DB L3 CompliantGeMS DB v1pt1Geochemical DataGeochemistryGeochronologyGeologicGeologic HazardsGeologic MapGeologyGisGlacialHazardsHelicopter SurveyLava FlowMorainesOutcrop SamplesPumiceRadiocarbon AgesRadiocarbon DatingRhyoliteRock GlaciersScoriaSubductionVolcanicVolcanic ArcVolcanic AshVolcanic EruptionVolcanic RocksVolcaniclastic DepositsVolcaniclasticsVolcanoesAlaska Division of Geological & Geophysical SurveysAleutian IslandsBering SeaColorado CreekCrater CreekDutch HarborJag PeakMount RecheshnoiMount VsevidofOkmokOkmok CalderaOkmok Hot SpringsOkmok VolcanoOkmok, MountPacific OceanReindeer CreekTulikUmnak IslandAlaska Division of Geological & Geophysical SurveysCrater Creek BasaltWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaHolocenePleistoceneThis report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical
3354 College Road
FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.Geophysical Institute and the Alaska Division of Geological & Geophysical Surveys, currently Cooperative Agreement G19AC00171, and by USGS Volcano Hazards Program funding to the Alaska Volcano Observatory. We thank many geologists and geophysicists who provided their time, insights, and camaraderie at Fort Glenn in all kinds of weather, including Jim Beget, Deb Bergfeld, Alain Burgisser, Michelle Coombs, Cheryl Cameron, John Eichelberger, Jeff Freymueller, Rick Hazlett, Alexander Max Kaufman, David Lescinsky, Taryn Lopez, Doerte Mann, Steve McNutt, Michael Ort, and Guy Tytgat. Former undergraduate and graduate students who participated in the geology fieldwork at Okmok Volcano include a cohort from Pomona College and the University of Alaska Fairbanks: Leslie Almberg, Matt Patrick, Ben Finney, Delanora Grey, Ken Papp, Joel Unema, and Lily Wong. Reviews by Tim Orr, Julie Nolan, and Drew Downs provided helpful insight and are much appreciated. Bering Pacific Ranches Ltd. supported this work through lodging and logistics support. Access to Umnak Island was by charter flights or boat from the Port of Dutch Harbor. We thank Cliff Gill (Airborne Scientific), Don Graves (Miss Peppers), and Jimmer MacDonald (Miss Alyssa) for safe transport to Umnak Island in often challenging sea conditions. Maritime Helicopters and pilots Bill Springer, Rick Farrish, and Jon Combs made our work possible, providing efficient, safe, and professional transportation in the field area. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The geologic map database was converted to GeMS, quality controlled, and then finalized by DGGS staff Amy Macpherson and Mike Hendricks.Attribute fields within each feature class are populated using the map symbology and corresponding applicable values from the GeMS and AK GeMS specifications. When known, certainty in attribute interpretation is indicated in the relevant fields. Attribute accuracy varies throughout the map and is scale-dependent.All polygon features were topologically validated according to the AK GeMS geologic mapping schema specifications.This publication is part of a DGGS Report of Investigations (RI). An RI is the completed product of original research and analysis, and RIs use professional cartography and undergo rigorous peer review, editing, and revision.Certainty in feature boundaries or location varies throughout the map. Data fields within each feature class and the accompanying orientation and location confidence lookup tables record the authors' degree of confidence in the location of applicable features.Ekberg, P.G.Hendricks, M.D.Athey, J.E.2021AK GeMS symbology: A description of the AK GeMS style fileMiscellaneous PublicationMP 169Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys7 phttps://doi.org/10.14509/30584paper2021publication dateEkberg, P.G. and others, 2021GIS analysis and digital cartographyHendricks, M.D.Ekberg, P.G.Athey, J.E.Wyatt, W.C.Willingham, A.L.Naibert, T.J.2021AK GeMS data dictionary: A description of the Alaska geologic mapping schemaMiscellaneous PublicationMP 170Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys10 phttps://doi.org/10.14509/30669paper2021publication dateHendricks, M.D. and others, 2021GIS analysis and digital cartographyU.S. Geological Survey National Cooperative Geologic Mapping Program2020GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic mapsTechniques and MethodsTM 11-B10United StatesU.S. Geological Survey1 phttps://dggs.alaska.gov/pubs/id/30585paper2020publication dateU.S. Geological Survey National Cooperative Geologic Mapping Program, 2020GIS analysis and digital cartographyGeologic mapping - A team of five geologists from AVO (UAF/GI and USGS partner agencies) began geologic work at Okmok Volcano in July 1998. Fieldwork was on foot, except for passenger truck transportation to the Crater Creek region. For the next 2 years, repeated visits to the island in summer involved fieldwork, mainly on foot or via an all-terrain vehicle (ATV). In June 2001, helicopter-supported geologic fieldwork was conducted while installing a seismic network. The helicopter support facilitated access to important outcrop sites and helped accelerate the pace of mapping, stratigraphic work, and sample collection for geochemistry and geochronology. The last field season before the 2008 eruption was in September 2004, during which most of the focus was on completing the map and hazards report, describing the stratigraphy and ages of late Pleistocene to recent eruptions from Okmok Volcano, and sampling for geochronology and geochemistry. Our objective was characterization of the Holocene eruptive history of Okmok Volcano, so we focused on mapping and describing deposits that we recognized to be postglacial (~12,000 yBP). Other work focused on separating, sampling, and describing the two caldera-forming eruptions to understand the potential for Okmok Volcano to produce highly explosive (VEI 4-6) eruptions. With little warning on July 12, 2008, Okmok Volcano began a 5-week-long eruption characterized by sustained explosive phreatomagmatic activity. Geologists from AVO visited the island during the eruption from July 31 to August 3. They gathered estimates of plume heights, ash samples from the eastern flanks of the volcano, observations from residents and fishing vessels, and photographs of the state of the caldera floor in the eastern sector near the active vent, to the extent safely possible. After the cessation of the eruption, a second AVO field team visited the island for a week in September 2008. This trip focused on measurements of ash deposit thickness in many places around the flanks and within the caldera, sample collection, reconnaissance stratigraphy, measurements of modified and new lake elevations, observations of lahar deposits and lahar deltas, and repair of geophysical monitoring equipment. Geologists from AVO and Northern Arizona University (NAU) returned to Okmok Volcano from July to August 2010 to investigate the 2008 eruptive products thoroughly. The work focused on detailed mapping of 2008 deposits, including ballistics, ash fall, and surge deposits on Umnak Island. Michael Ort and Joel Unema of NAU performed detailed stratigraphy and physical volcanology work. The team also resurveyed intracaldera lake elevations, documented erosion of the 2008 Ahmanilix tuff cone, and documented vents, pyroclastic deposits, and collapse features within the caldera. Standard GIS techniques were used to compile maps, incorporate field geologists' notes and sketches, and merge those with digitized, previously mapped units. Basemap contours and shaded relief imagery were derived by combining pre-2008-eruption digital elevation model (DEM) data from both NASA's shuttle radar topography mission (SRTM) and the aircraft-mounted synthetic aperture radar (AirSAR) mission. Radiocarbon and 40Ar/39Ar age dating allowed us to determine rock unit ages. The accompanying map or report provides a comprehensive bibliographic reference list of prior work used to identify and delineate rock units and structural elements.2023GIS analysis and digital cartography - This data distribution package's geologic and geographic features were organized and attributed according to the AK GeMS geologic mapping schema. The data were programmatically transformed to provide download options in three formats: (1) an AK GeMS data package that includes the complete AK GeMS database and associated files, (2) a GeMS data package that is a conversion of the AK GeMS database into the base GeMS standard published by the USGS, and (3) a shapefile data package that includes two simple shapefile representations of the data.Ekberg, P.G. and others, 2021Hendricks, M.D. and others, 2021U.S. Geological Survey National Cooperative Geologic Mapping Program, 20202023vectorUniversal Transverse Mercator20.999600-1710500000.0000000coordinate pair.00000001.00000001MetersNAD83GRS 806378137298.257222101okmok_ak_gems_db_pkgGeodatabase, layer files, style files, and fontsDGGSokmok_ak_gems_db_pkgokmok_gems_db_pkgGeodatabase, layer files, style files, and fontsDGGSokmok_gems_db_pkgokmok_gems_shapefile_pkgShapefiles and open data filesDGGSokmok_gems_shapefile_pkgAlaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical
3354 College Road
FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.RI 2023-1The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount.Contact DGGS for current pricinggeodatabasegeologic maphttps://doi.org/10.14509/31015Free download20231207Alaska Division of Geological & Geophysical SurveysSimone MontayneMetadata Managermailing and physical
3354 College Road
FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys.https://dggs.alaska.gov/metadata/dggs.extdggs metadata extensions","source_transform":null,"status":"error"}