Identification_Information: Citation: Citation_Information: Originator: Suleimani, E.N. Originator: Salisbury, J.B. Originator: Nicolsky, D.J. Publication_Date: 2022 Title: Tsunami inundation maps for Karluk and Larsen Bay, Kodiak Island, Alaska Geospatial_Data_Presentation_Form: report, data Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2022-2 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 42 p., 2 sheets Online_Linkage: https://doi.org/10.14509/30892 Description: Abstract: Tsunami inundation maps for Karluk and Larsen Bay, Kodiak Island, Alaska, Report of Investigation 2022-2, identifies potential tsunami hazards for the Kodiak Island communities of Karluk and Larsen Bay, Alaska, by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquakes. Credible worst-case scenarios are defined by analyzing the tsunami dynamics related to various plausible earthquake slip distributions along the Alaska-Aleutian megathrust. Potential worst-case tsunami sources include megathrust earthquakes in the Kodiak Island region with a magnitude range of Mw9.0 to Mw9.3. We do not include impacts of subaerial or submarine landslide tsunami sources, as that is beyond the scope of this study. A hypothetical earthquake near Kodiak Island with maximum slip distributed between 10 and 40 km depth (6.2-24.85 mi) results in 'worst case' tsunami-inundation for both Karluk and Larsen Bay. The maximum predicted overland flow depth ranges from 5 to 10 m (17 to 33 ft) in Karluk and from 10 to 15 m (33 to 49 ft) in Larsen Bay. The currents can be as strong as 4 m/sec (7.8 knots) in Karluk River and 7 m/sec (13.6 knots) in Larsen Bay. Dangerous wave activity is expected to last for at least 12 hours after the hypothetical worst-case earthquakes. Tsunami inundation maps that accompany this report represent a combination of numerous tsunami scenarios to show the maximum composite extent of inundation from these models. The results presented here are intended to provide guidance to local emergency management agencies for tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami damage. The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/30892. Purpose: DGGS manages the DNR portion of the federally funded National Tsunami Hazard Mitigation Program (NTHMP). The program identifies at-risk coastal Alaska communities and provides tsunami hazard maps for hazard mitigation and emergency response training. Supplemental_Information: >max-flow-depth: Raster image depicting maximum composite flow depths over dry land. For each grid point, the pixel value provides the modeled depth of water (in meters) over previously dry land, representing the maximum depth value of all calculated tsunami scenarios. >max-inundation: Estimated, "maximum credible scenario" inundation line(s) that encompasses the maximum extent of flooding based on model simulation of all credible source scenarios and historical observations. The maximum credible scenario inundation lines are intended to be utilized as a basis for local tsunami hazard planning and development of evacuation maps. >scenario-01: Mw 9.2 earthquake near Kodiak Island; 20 km depth >scenario-02: Mw 9.0 earthquake near Kodiak Island; 30 km depth >scenario-03: Mw 9.3 earthquake near Kodiak Island; 20-30 km depth >scenario-04: Mw 9.27 earthquake near Kodiak Island; 20-30 km depth, slip skewness parameter = 0.2 >scenario-05: Mw 9.18 earthquake near Kodiak Island; 20-30 km depth, slip skewness parameter = 0.7 >scenario-06: Mw 9.3 earthquake near Kodiak Island; 10 km depth, slip extending to 0 km depth >scenario-07: Mw 9.3 earthquake with 35 m of maximum slip across the majority of the rupture >scenario-08: Mw 9.3 earthquake with 50 m of maximum slip in the shallow part of the rupture >scenario-09: Mw 9.1 earthquake in the Cascadia subduction zone Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2022 Currentness_Reference: publication date Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -154.522239 East_Bounding_Coordinate: -153.919990 North_Bounding_Coordinate: 57.606735 South_Bounding_Coordinate: 57.521259 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Active Fault Theme_Keyword: Bathymetry Theme_Keyword: Coastal Theme_Keyword: Coastal and River Theme_Keyword: DGGS Theme_Keyword: Earthquake Theme_Keyword: Earthquake Related Slope Failure Theme_Keyword: Emergency Preparedness Theme_Keyword: Engineering Theme_Keyword: Engineering Geology Theme_Keyword: Environmental Theme_Keyword: Fault Displacement Theme_Keyword: Faulting Theme_Keyword: Faults Theme_Keyword: Flood Theme_Keyword: Geologic Theme_Keyword: Geologic Hazards Theme_Keyword: Geological Process Theme_Keyword: Geotechnical Theme_Keyword: Hazards Theme_Keyword: Inundation Theme_Keyword: Land Subsidence Theme_Keyword: Landslide Theme_Keyword: Marine Theme_Keyword: Marine Geology Theme_Keyword: Modeling Theme_Keyword: Neotectonics Theme_Keyword: Seismic Hazards Theme_Keyword: Seismic Interpretation Theme_Keyword: Subduction Theme_Keyword: Subsidence Theme_Keyword: Surface Theme_Keyword: Topography Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Cape Karluk Place_Keyword: Karluk Place_Keyword: Karluk Lagoon Place_Keyword: Karluk River Place_Keyword: Kodiak Island Place_Keyword: Larsen Bay Place_Keyword: Shelikof Strait Place_Keyword: Tanglefoot Bay Place_Keyword: Uyak Bay 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: This dataset includes results of numerical modeling of earthquake-generated tsunami waves for a specific community. Modeling was completed using the best information and tsunami modeling software available at the time of analysis. They are numerical solutions and, while they are believed to be accurate, their ultimate accuracy during an actual tsunami will depend on the specifics of earth deformations, on-land construction, tide level, and other parameters at the time of the tsunami. Actual areas of inundation may differ from areas shown in this dataset. Landslide tsunami sources may not be included in the modeling due to unknown potential impact of such events on a given community; please refer to accompanying report for more information on tsunami sources used for this study. The limits of inundation shown should only be used as a general guideline for emergency planning and response action in the event of a major tsunamigenic earthquake. These results are not intended for any other use, including land-use regulation or actuarial purposes. 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: This report was funded by the U.S. Department of Commerce/National Oceanic and Atmospheric Administration (NOAA) through National Tsunami Hazard Mitigation Program Awards NA20NWS4670057 and NA21NWS4670003 to the Alaska Division of Homeland Security & Emergency Management in partnership with the Alaska Earthquake Center and the Alaska Division of Geological & Geophysical Surveys. This does not constitute an endorsement by NOAA. Numerical calculations for this work were supported by High-Performance Computing (HPC) resources at the Research Computing Systems unit at the Geophysical Institute, University of Alaska Fairbanks. We thank our reviewers, Corina Allen and one anonymous reviewer, for insightful comments and suggestions that improved the report. Cross_Reference: Citation_Information: Originator: Newell, J.T. Originator: Maurits, S.A. Originator: Suleimani, E.N. Originator: Koehler, R.D. Originator: Nicolsky, D.J. Publication_Date: 2015 Title: Tsunami inundation maps for Alaska communities Series_Information: Series_Name: Digital Data Series Issue_Identification: DDS 10 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Online_Linkage: https://doi.org/10.14509/29523 Cross_Reference: Citation_Information: Originator: Salisbury, J.B. Originator: Janssen, K.A. Publication_Date: 2022 Title: Tsunamis in Alaska Series_Information: Series_Name: Information Circular Issue_Identification: IC 85 v. 2 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 2 p Online_Linkage: https://doi.org/10.14509/30849 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The maps showing the results of our modeling have been completed using the best information available and are believed to be accurate, however, their preparation required many assumptions. We described several scenarios and provide an estimate of maximum credible tsunami inundation. Actual conditions during a tsunami event may vary from those considered, so the accuracy cannot be guaranteed. The limits of inundation shown should be used only as a guideline for emergency planning and response action. Actual areas inundated will depend on specifics of the earth deformations, on-land construction, and tide level, and they may differ from areas shown on the map. The information on this map is intended to provide a basis for state and local agencies to plan emergency evacuation and tsunami response actions in the event of a major tsunamigenic earthquake. These results are not intended for land-use regulation or building-code development. This DGGS Report of Investigations is a final report of scientific research. Several scientists familiar with the subject matter provided technical reviews. Uncertainties associated with the depiction or interpretation of various features are discussed in the manuscript. Logical_Consistency_Report: Not applicable Completeness_Report: Our modeling results have been completed using the best information available and are believed to be accurate; however, their preparation required many assumptions, and actual conditions during a tsunami event may vary from those considered. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The hydrodynamic model used to calculate propagation and runup of tsunami waves is a nonlinear, flux-formulated, shallow-water model that has passed the validation and verification tests required for models used in the production of tsunami inundation maps. The uncertainties in tsunami modeling include bottom friction, the presence or absence of buildings and vegetation in DEMs, the time delay between the observed and computed tsunami arrivals discussed above, the lack of horizontal deformation in the displacement models, and the assumption of instantaneous displacement. The tsunami scenarios we calculate in this report are considered sufficient to capture the worst-case tsunami event. However, there are still an infinite number of possible slip distributions. Further details about the limitations of the employed modeling approach are described in earlier reports by Suleimani and others and Nicolsky and others, as well as in National Tsunami Hazard Mitigation Program guidelines. See the accompanying report for more detail. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: The vertical accuracy of the inundation modeling is dependent on the accuracy and resolution of the digital elevation models (DEMs) and tidal datum values that were used to compile the computational grid. We provide additional details about DEM and grid development in the accompanying report. Prior to scenario modeling, bathymetric data were shifted to use Mean Higher High Water (MHHW) as the vertical datum. The depths of inundation shown should be used only as a guideline for emergency planning and response action. Actual inundation water depth will depend on specifics of the earth deformations, on-land construction, and tide level, and they may differ from areas shown by this data. The information is intended to permit state and local agencies to plan emergency evacuation and tsunami response actions in the event of a major tsunamigenic earthquake. These results are not intended for land-use regulation or building-code development. For additional information, please reference the sources of errors and uncertainties section of the accompanying report. Lineage: Process_Step: Process_Description: Model validation - The numerical model that we used for simulation of tsunami wave propagation and runup was validated through a set of analytical benchmarks and tested against laboratory data. The model solves water equations using a finite-difference method on a staggered grid. See the accompanying report for more detail and additional model information. Process_Date: 2014 Process_Step: Process_Description: Development of nested grids - To support inundation modeling of coastal areas in Alaska, we used a series of nested telescoping grids, or digital elevation models (DEMs), as input layers for tsunami inundation modeling and mapping. These grids of increasing resolution allowed us to propagate waves generated by various sources to Karluk and Larsen Bay. In order to propagate a wave from its source to various coastal locations, we used embedded grids, placing a large, coarse grid in deep water and coupling it with smaller, finer grids in shallow water areas. The extent of each grid used for our tsunami inundation mapping is listed in the accompanying report. Process_Date: 2021 Process_Step: Process_Description: Numerical simulations of hypothetical tsunami scenarios - We assessed hazards related to tectonic tsunamis in Karluk and Larsen Bay by performing model simulations for each hypothetical source scenario. For each tsunami scenario, we first calculate the maximum tsunami wave heights in the highest-resolution grid over the course of the entire model run in the following way: at each grid point, the tsunami wave height is computed at every time step during the tsunami propagation time and the maximum value is kept. Then we compute the composite maximum tsunami wave height from all considered scenarios by again choosing the maximum value for each grid point among all scenarios, and plot the results. Process_Date: 2022 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: vector Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: .000001 Longitude_Resolution: .000001 Geographic_Coordinate_Units: decimal degrees Geodetic_Model: Horizontal_Datum_Name: WGS84 Ellipsoid_Name: WGS 84 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257223563 Vertical_Coordinate_System_Definition: Depth_System_Definition: Depth_Datum_Name: Mean Higher High Water Depth_Resolution: .01 Depth_Distance_Units: meter Depth_Encoding_Method: Attribute values Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-karluk-max-flow-depth.tif, ri2022-2-larsen-bay-max-flow-depth.tif Entity_Type_Definition: Raster image depicting maximum composite flow depths over dry land. For each grid point, the pixel value provides the modeled depth of water (in meters) over previously dry land, representing the maximum depth value of all calculated tsunami scenarios. File format: Entity_Type_Definition_Source: Alaska Earthquake Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: max-flow-depth Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-karluk-max-inundation.shp, ri2022-2-larsen-bay-max-inundation.shp Entity_Type_Definition: Estimated, "maximum credible scenario" inundation line(s) that encompasses the maximum extent of flooding based on model simulation of all credible source scenarios and historical observations. The maximum credible scenario inundation lines are intended to be utilized as a basis for local tsunami hazard planning and development of evacuation maps. File format: Entity_Type_Definition_Source: Alaska Earthquake Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: max-inundation Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-01-karluk-flow-depth.tif, ri2022-2-scenario-01-karluk-inundation.shp, ri2022-2-scenario-01-larsen-bay-flow-depth.tif, ri2022-2-scenario-01-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.2 earthquake near Kodiak Island; 20 km depth File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-01 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-02-karluk-flow-depth.tif, ri2022-2-scenario-02-karluk-inundation.shp, ri2022-2-scenario-02-larsen-bay-flow-depth.tif, ri2022-2-scenario-02-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.0 earthquake near Kodiak Island; 30 km depth File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-02 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-03-karluk-flow-depth.tif, ri2022-2-scenario-03-karluk-inundation.shp, ri2022-2-scenario-03-larsen-bay-flow-depth.tif, ri2022-2-scenario-03-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.3 earthquake near Kodiak Island; 20-30 km depth File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-03 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-04-karluk-flow-depth.tif, ri2022-2-scenario-04-karluk-inundation.shp, ri2022-2-scenario-04-larsen-bay-flow-depth.tif, ri2022-2-scenario-04-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.27 earthquake near Kodiak Island; 20-30 km depth, slip skewness parameter = 0.2 File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-04 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-05-karluk-flow-depth.tif, ri2022-2-scenario-05-karluk-inundation.shp, ri2022-2-scenario-05-larsen-bay-flow-depth.tif, ri2022-2-scenario-05-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.18 earthquake near Kodiak Island; 20-30 km depth, slip skewness parameter = 0.7 File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-05 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-06-karluk-flow-depth.tif, ri2022-2-scenario-06-karluk-inundation.shp, ri2022-2-scenario-06-larsen-bay-flow-depth.tif, ri2022-2-scenario-06-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.3 earthquake near Kodiak Island; 10 km depth, slip extending to 0 km depth File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-06 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-07-karluk-flow-depth.tif, ri2022-2-scenario-07-karluk-inundation.shp, ri2022-2-scenario-07-larsen-bay-flow-depth.tif, ri2022-2-scenario-07-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.3 earthquake with 35 m of maximum slip across the majority of the rupture File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-07 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-08-karluk-flow-depth.tif, ri2022-2-scenario-08-karluk-inundation.shp, ri2022-2-scenario-08-larsen-bay-flow-depth.tif, ri2022-2-scenario-08-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.3 earthquake with 50 m of maximum slip in the shallow part of the rupture File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-08 Detailed_Description: Entity_Type: Entity_Type_Label: ri2022-2-scenario-09-karluk-flow-depth.tif, ri2022-2-scenario-09-karluk-inundation.shp, ri2022-2-scenario-09-larsen-bay-flow-depth.tif, ri2022-2-scenario-09-larsen-bay-inundation.shp Entity_Type_Definition: Mw 9.1 earthquake in the Cascadia subduction zone File format: Entity_Type_Definition_Source: Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report Entity_Attribute_Layer_Name: scenario-09 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 2022-2 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: Shapefiles and Raster data Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.14509/30892 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20220920 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