Identification_Information: Citation: Citation_Information: Originator: Suleimani, E.N. Originator: Nicolsky, D.J. Originator: Salisbury, J.B. Publication_Date: 2020 Title: Regional tsunami hazard assessment for communities of Bristol Bay and the Pribilof Islands, Alaska Geospatial_Data_Presentation_Form: report and digital data Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2020-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 32 p., 6 sheets Online_Linkage: http://doi.org/10.14509/30422 Description: Abstract: We assess potential tsunami hazards for the communities of Dillingham, Nelson Lagoon, and Platinum in Bristol Bay, and St. Paul and St. George on the Pribilof Islands. The Bristol Bay communities have no high-resolution bathymetry or topography, therefore we conduct tsunami hazard assessments for these areas at the regional scale. The regional approach is a suitable, cost-effective approximation and replacement for high-resolution tsunami inundation maps. The Pribilof Islands communities do have the high-resolution baseline data necessary to produce high-resolution maps. The primary tsunami hazard considered for communities in this report originate from tsunamigenic earthquakes along the Alaska-Aleutian subduction zone and from underwater slope failures in the Bering Sea. Volcanic tsunamis are known to have generated waves up to 12 m in Bristol Bay about 3,500 years ago, but we do not model them in this study due to insufficient data on locations and volumes of these potential hazards. We numerically model tsunamis generated by eight different megathrust earthquakes and two landslide sources, analyze tsunami wave dynamics, and develop tsunami hazard maps. The tectonic tsunami scenarios that we examined simulate Mw 9.2 megathrust earthquakes with a slip distribution in the 5-35 km (3-22 mi) depth range along the Aleutian megathrust. The landslide tsunami scenarios include submarine mass failures on both sides of Umnak Plateau. The maximum assumed runup heights are 1.4 m (4.6 ft) for Dillingham, 3.5 m (11.5 ft) for Nelson Lagoon, and 4.9 m (16 ft) for Platinum. The maximum calculated tsunami runup in St. Paul is 16 m (52.5 ft); it is 5m (16 ft) in St. George, and 11 m (36 ft) near the St. George airport. Results presented here are intended to provide guidance to local emergency management agencies in initial tsunami inundation assessment, evacuation planning, and public education for mitigation of future tsunami hazards.The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/30422. Purpose: Results presented here are intended to provide guidance to local emergency management agencies in tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards. Supplemental_Information: >hazard-boundary: Shapefiles depicting maximum assumed runup heights with an included safety factor. These lines are intended to be utilized as a basis for local tsunami hazard planning and the development of evacuation maps. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2018 Ending_Date: 2020 Currentness_Reference: publication date Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -170.299255 East_Bounding_Coordinate: -158.437750 North_Bounding_Coordinate: 59.069741 South_Bounding_Coordinate: 55.999827 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Coastal Theme_Keyword: Coastal and River 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: Geology Theme_Keyword: Geotechnical Theme_Keyword: Hazards Theme_Keyword: Inundation Theme_Keyword: Land Subsidence Theme_Keyword: Marine Geology Theme_Keyword: Modeling Theme_Keyword: Neotectonics Theme_Keyword: Seismic Hazards Theme_Keyword: Subsidence Theme_Keyword: Surface Theme_Keyword: Tectonics Theme_Keyword: Topography Theme_Keyword: Tsunami Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Bering Sea Place_Keyword: Bristol Bay Place_Keyword: Dillingham Place_Keyword: Nelson Lagoon Place_Keyword: Platinum Place_Keyword: Pribilof Islands Quadrangle Place_Keyword: Saint George Place_Keyword: Saint Paul Place_Keyword: Saint Paul Island 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 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 Data_Set_Credit: This project received support from the National Oceanic and Atmospheric Administration (NOAA) under grant awards: NA16NWS4670030, NA17NWS4670006, and NA19NWS4670008 with the State of Alaska's Division of Homeland Security & Emergency Management. Numerical calculations for this work were supported by a grant of High Performance Computing (HPC) resources from the Arctic Region Supercomputing Center (ARSC) at the University of Alaska Fairbanks. Cross_Reference: Citation_Information: Originator: Nicolsky, D.J. Originator: Suleimani, E.N. Originator: Freymueller, J.T. Originator: Koehler, R.D. Publication_Date: 2015 Title: Tsunami inundation maps of Fox Islands communities, including Dutch Harbor and Akutan, Alaska Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2015-5 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 67 p., 2 sheets, scale 1:12,500 Online_Linkage: http://doi.org/10.14509/29414 Cross_Reference: Citation_Information: Originator: Suleimani, E.N. Originator: Salisbury, J.B. Originator: Nicolsky, D.J. Originator: West, M.E. Publication_Date: 2019 Title: Tsunami inundation maps for Adak and Atka, Alaska Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2019-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 63 p., 6 sheets Online_Linkage: http://doi.org/10.14509/30186 Cross_Reference: Citation_Information: Originator: Suleimani, E.N. Originator: Nicolsky, D.J. Originator: Koehler, R.D. Originator: Freymueller, J.T. Originator: Macpherson, A.E. Publication_Date: 2016 Title: Tsunami inundation maps for King Cove and Cold Bay communities, Alaska Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2016-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 73 p., 2 sheets, scale 1:12,500 Online_Linkage: http://doi.org/10.14509/29565 Cross_Reference: Citation_Information: Originator: Suleimani, E.N. Originator: Salisbury, J.B. Originator: Nicolsky, D.J. Originator: Koehler, R.D. Publication_Date: 2019 Title: Regional tsunami hazard assessment for False Pass and Perryville, Alaska Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2019-3 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 16 p., 2 sheets Online_Linkage: http://doi.org/10.14509/30192 Cross_Reference: Citation_Information: Originator: Nicolsky, D.J. Originator: Suleimani, E.N. Originator: Koehler, R.D. Publication_Date: 2016 Title: Tsunami inundation map for the village of Nikolski, Alaska Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2016-7 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 34 p., 1 sheet, scale 1:12,500 Online_Linkage: http://doi.org/10.14509/29674 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The hydrodynamic model used to calculate propagation and runup of tectonic tsunamis is a nonlinear, flux-formulated, shallow-water model and has passed the required tests for official use in producing tsunami inundation maps. Most of the uncertainties in the numerical calculations originate from the tsunamigenic earthquake sources used in the models. Uncertainties in the earthquakes, such as the precise location, magnitude, and slip distribution, are the largest sources of error. The direction, amplitude, and arrival times of incoming waves are determined by the initial ocean surface conditions immediately following the earthquake. Therefore, the modeling results are particularly sensitive to the details of the tsunamigenic earthquake rupture, and when the earthquake occurs close to a community, discrepancies can be exacerbated. Furthermore, our assessment of potential earthquake scenarios is by no means exhaustive but represents the best estimate of the locations and sizes of potential tsunami-generating events. It is possible that other unrecognized earthquake scenarios could present hazards to these communities. 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: 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 and actual conditions during a tsunami event may vary from those considered. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: We model tsunami waves and inundation using a series of nested computational grids. A nested grid allows for higher resolution computations in areas where detail is needed while minimizing computer runtime in areas where such detail is not required. The bathymetric and topographic relief in each nested grid is based on DEMs developed at the NCEI. The extent of each grid used for the Bristol Bay and Pribilof Islands mapping project is shown in figure 3 and listed in table 2. The coarsest grid (level 0), with 2-arc-minute (approximately 2 km) resolution, spans the central and northern Pacific Ocean. The bathymetric data for the 2-arc-minute-resolution grid is extracted from the ETOPO2 dataset. We use two intermediate grids between the coarsest- and highest-resolution grids (table 2). The data sources and methodology used to develop the 24-arc-second DEMs are described in detail by Lim and others (2011). The 8- and 8/3-arc-second DEMs were developed by the NCEI in the scope of NTHMP. The spatial resolution of the fine resolution grid cells, which is ~48 x 82 m (157 x 269 ft), satisfies NOAA's minimum recommended requirements for estimation of the tsunami hazard zone. We stress that this grid spacing is not adequate for the high-resolution modeling of the inundation zone and no DEM verification efforts were conducted to reduce uncertainties in the fine resolution grids for Dillingham, Nelson Lagoon, and Platinum. Therefore, in this report we perform high-resolution runup modeling only for the communities of St. Paul and St. George. For the communities of Dillingham, Nelson Lagoon, and Platinum we provide an estimation of the tsunami hazard zone by extrapolating the maximum composite tsunami wave height onto land according to the tsunami scenarios described below. We account for uncertainties inherent to this method by applying a 30 percent safety factor to the estimated hazard zone. 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 associated manuscript. 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: 2011 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 Dillingham, Nelson Lagoon, and Platinum, St. Paul, and St. George. 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: 2018 Process_Step: Process_Description: Numerical simulations of hypothetical tsunami scenarios - We assessed hazards related to tectonic tsunamis in Dillingham, Nelson Lagoon, and Platinum, St. Paul, and St. George 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: 2018 Process_Step: Process_Description: Tsunami hazard boundary - After calculating the maximum tsunami height for every grid point in the vicinity of a community, we multiply each highest value grid point by a safety factor of 1.3 (30%) and define it as the maximum runup height. Then we find an elevation contour on the DCRA community map that corresponds to this maximum runup height. This contour is the tsunami hazard boundary. Process_Date: 2018 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: World Geodetic System of 1984 Ellipsoid_Name: WGS 84 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257223563000025 Vertical_Coordinate_System_Definition: Depth_System_Definition: Depth_Datum_Name: Mean Higher High Water Depth_Resolution: 1 Depth_Distance_Units: meter Depth_Encoding_Method: Attribute values Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: hazard-boundary Entity_Type_Label: ri2020-1-hazard-boundary-dillingham.shp, ri2020-1-hazard-boundary-nelson-lagoon.shp, ri2020-1-hazard-boundary-platinum.shp, ri2020-1-hazard-boundary-st-george.shp, ri2020-1-hazard-boundary-st-paul.shp Entity_Type_Definition: Shapefiles depicting maximum assumed runup heights with an included safety factor. These lines are intended to be utilized as a basis for local tsunami hazard planning and the development of evacuation maps. File format: shapefile Entity_Type_Definition_Source: Alaska Earthquake Center, Geophysical Institute, University of Alaska, this report 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 Resource_Description: RI 2020-1 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. 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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: http://www.dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions