Identification_Information: Citation: Citation_Information: Originator: Larsen, J.F. Originator: Neal, C.A. Originator: Schaefer, J.R. Originator: Nye, C.J. Publication_Date: 2023 Title: Geologic map of Okmok Volcano Geospatial_Data_Presentation_Form: geodatabase Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2023-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 63 p., 4 sheets Online_Linkage: https://doi.org/10.14509/31015 Description: Abstract: Geologic 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. Purpose: 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. Supplemental_Information: 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/10.14509/30584 Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1983 Ending_Date: 2023 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -168.441430 East_Bounding_Coordinate: -167.779982 North_Bounding_Coordinate: 53.576449 South_Bounding_Coordinate: 53.221880 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: 40Ar/39Ar Theme_Keyword: Ashfall Theme_Keyword: Caldera Theme_Keyword: DGGS Theme_Keyword: Fumarole Chemistry Theme_Keyword: GeMS DB L3 Compliant Theme_Keyword: GeMS DB v1pt1 Theme_Keyword: Geochemical Data Theme_Keyword: Geochemistry Theme_Keyword: Geochronology Theme_Keyword: Geologic Theme_Keyword: Geologic Hazards Theme_Keyword: Geologic Map Theme_Keyword: Geology Theme_Keyword: Gis Theme_Keyword: Glacial Theme_Keyword: Hazards Theme_Keyword: Helicopter Survey Theme_Keyword: Lava Flow Theme_Keyword: Moraines Theme_Keyword: Outcrop Samples Theme_Keyword: Pumice Theme_Keyword: Radiocarbon Ages Theme_Keyword: Radiocarbon Dating Theme_Keyword: Rhyolite Theme_Keyword: Rock Glaciers Theme_Keyword: Scoria Theme_Keyword: Subduction Theme_Keyword: Volcanic Theme_Keyword: Volcanic Arc Theme_Keyword: Volcanic Ash Theme_Keyword: Volcanic Eruption Theme_Keyword: Volcanic Rocks Theme_Keyword: Volcaniclastic Deposits Theme_Keyword: Volcaniclastics Theme_Keyword: Volcanoes Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Aleutian Islands Place_Keyword: Bering Sea Place_Keyword: Colorado Creek Place_Keyword: Crater Creek Place_Keyword: Dutch Harbor Place_Keyword: Jag Peak Place_Keyword: Mount Recheshnoi Place_Keyword: Mount Vsevidof Place_Keyword: Okmok Place_Keyword: Okmok Caldera Place_Keyword: Okmok Hot Springs Place_Keyword: Okmok Volcano Place_Keyword: Okmok, Mount Place_Keyword: Pacific Ocean Place_Keyword: Reindeer Creek Place_Keyword: Tulik Place_Keyword: Umnak Island Stratum: Stratum_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Stratum_Keyword: Crater Creek Basalt Temporal: Temporal_Keyword_Thesaurus: Walker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of America Temporal_Keyword: Holocene Temporal_Keyword: Pleistocene Access_Constraints: This 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). Use_Constraints: 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please 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. Data_Set_Credit: 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. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: 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. Logical_Consistency_Report: All polygon features were topologically validated according to the AK GeMS geologic mapping schema specifications. Completeness_Report: 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. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: 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. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Ekberg, P.G. Originator: Hendricks, M.D. Originator: Athey, J.E. Publication_Date: 2021 Title: AK GeMS symbology: A description of the AK GeMS style file Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 169 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 7 p Online_Linkage: https://doi.org/10.14509/30584 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2021 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Ekberg, P.G. and others, 2021 Source_Contribution: GIS analysis and digital cartography Source_Information: Source_Citation: Citation_Information: Originator: Hendricks, M.D. Originator: Ekberg, P.G. Originator: Athey, J.E. Originator: Wyatt, W.C. Originator: Willingham, A.L. Originator: Naibert, T.J. Publication_Date: 2021 Title: AK GeMS data dictionary: A description of the Alaska geologic mapping schema Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 170 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 10 p Online_Linkage: https://doi.org/10.14509/30669 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2021 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Hendricks, M.D. and others, 2021 Source_Contribution: GIS analysis and digital cartography Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey National Cooperative Geologic Mapping Program Publication_Date: 2020 Title: GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic maps Series_Information: Series_Name: Techniques and Methods Issue_Identification: TM 11-B10 Publication_Information: Publication_Place: United States Publisher: U.S. Geological Survey Other_Citation_Details: 1 p Online_Linkage: https://dggs.alaska.gov/pubs/id/30585 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2020 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020 Source_Contribution: GIS analysis and digital cartography Process_Step: Process_Description: Geologic 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. Process_Date: 2023 Process_Step: Process_Description: GIS 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. Source_Used_Citation_Abbreviation: Ekberg, P.G. and others, 2021 Source_Used_Citation_Abbreviation: Hendricks, M.D. and others, 2021 Source_Used_Citation_Abbreviation: U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020 Process_Date: 2023 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: vector Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 2 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -171 Latitude_of_Projection_Origin: 0 False_Easting: 500000.000000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: .00000001 Ordinate_Resolution: .00000001 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: NAD83 Ellipsoid_Name: GRS 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257222101 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: okmok_ak_gems_db_pkg Entity_Type_Definition: Geodatabase, layer files, style files, and fonts Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: okmok_ak_gems_db_pkg Detailed_Description: Entity_Type: Entity_Type_Label: okmok_gems_db_pkg Entity_Type_Definition: Geodatabase, layer files, style files, and fonts Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: okmok_gems_db_pkg Detailed_Description: Entity_Type: Entity_Type_Label: okmok_gems_shapefile_pkg Entity_Type_Definition: Shapefiles and open data files Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: okmok_gems_shapefile_pkg Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please 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. Resource_Description: RI 2023-1 Distribution_Liability: The 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. Standard_Order_Process: Non-digital_Form: 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. Fees: Contact DGGS for current pricing Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: geodatabase Format_Information_Content: geologic map Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.14509/31015 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20231207 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Person: Simone Montayne Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Use_Constraints: If 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. Metadata_Extensions: Online_Linkage: https://dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions