{"action":"create","ckan_id":null,"date_created":"Sat, 21 Mar 2026 21:04:58 GMT","date_finished":null,"harvest_job_id":"79726ef4-fe9d-44a6-97a0-95f49b8db61f","harvest_source_id":"31f41541-38a0-400b-b240-10ebcb0acd9a","id":"808c656a-62a5-4b39-a784-f8e885010cdb","identifier":"https://dggs.alaska.gov/webpubs/metadata/RI2025-4.xml","parent_identifier":null,"source_hash":"f17e58f6f313164730440d59c69d0108f642d85f5ef2d9dbae9508b6172af918","source_raw":"Troshina, E.N.Salisbury, J.B.Nicolsky, D.J.2025Tsunami inundation map of False Pass, Alaskareport, dataReport of InvestigationRI 2025-4Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys38 p.https://doi.org/10.14509/31682Tsunami inundation map of False Pass, Alaska, Report of Investigation 2025-4, evaluates potential tsunami hazards for the community of False Pass, Alaska, by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquakes. We define an updated suite of earthquakes--including Tohoku-style megathrust ruptures and other sources in the western Alaska Peninsula region--to calculate vertical seafloor displacements and model resulting tsunami dynamics. A hypothetical earthquake with maximum slip distributed between depths of 10 and 20 km (6.2 and 12.4 mi) results in 'worst case' tsunami inundation in False Pass. If the tsunami arrives at high tide, the maximum predicted overland flow depths in the community can reach up to 10 m (32.8 ft), and the currents could be as strong as 15 m/sec (29 knots). Dangerous wave activity is expected to last for more than 12 hours. 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/10.14509/31682.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.>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.\t\r\n>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.2025publication datecompleteNone planned-163.420006-163.26210054.89267054.790150ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysActive FaultCoastalCoastal and RiverDGGSEarthquakeEmergency PreparednessEngineeringEngineering GeologyFaultingFaultsFloodGeologicGeologic HazardsGeological ProcessGeologyGeomorphologyGeotechnicalGround MotionHazardsInundationModelingNeotectonicsOutreachSeismic GapSeismic HazardsSeismic InterpretationSurfaceSurface WaterTectonicsAlaska Division of Geological & Geophysical SurveysAleutian IslandsAleutian PeninsulaBechevin BayCanyon CreekContact CreekFalse PassFriday CreekHerendeen BayIsanotski StraitKabuch PointNichols PointPalisade CliffsWhirl PointThis 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).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.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.This report was funded by the U.S. Department of Commerce/National Oceanic and Atmospheric Administration (NOAA) through National Tsunami Hazard Mitigation Program Awards NA21NWS4670003 and NA22NWS4670012 to the Alaska Division of Homeland Security and Emergency Management. This does not constitute an endorsement by NOAA. Numerical calculations for this work were supported by High Performance Computing resources at the Research Computing Systems unit at the Geophysical Institute of the University of Alaska Fairbanks.Newell, J.T.Maurits, S.A.Suleimani, E.N.Koehler, R.D.Nicolsky, D.J.2015Tsunami inundation maps for Alaska communitiesDigital Data SeriesDDS 10Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveyshttps://doi.org/10.14509/29523Nicolsky, D.J.Suleimani, E.N.Seitz, S.S.Montayne, SimoneSalisbury, J.B.2024Catalog of source data for tsunami inundation modeling in AlaskaDigital Data SeriesDDS 21Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveyshttps://doi.org/10.14509/30953Salisbury, J.B.Janssen, K.A.2022Tsunamis in AlaskaInformation CircularIC 85 v. 2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys2 phttps://doi.org/10.14509/30849Suleimani, E.N.Salisbury, J.B.Nicolsky, D.J.Koehler, R.D.2019Regional tsunami hazard assessment for False Pass and Perryville, AlaskaReport of InvestigationRI 2019-3Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys16 p., 2 sheets, scale 1:21,000https://doi.org/10.14509/30192The 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.Not applicableOur 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.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.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.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.2014Development 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 False Pass. 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.2024Numerical simulations of hypothetical tsunami scenarios - We assessed hazards related to tectonic tsunamis in False Pass by performing model simulations for each historic 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.2024vector.000001.000001decimal degreesWGS84WGS 846378137298.257223563Mean Higher High Water.01meterAttribute valuesri2024-4-anchor-point-max-flow-depth.tifRaster 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.Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this reportmax-flow-depthri2025-4-max-inundation.shpEstimated, 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.Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this reportmax-inundationAlaska 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 2025-4The 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 pricingShapefiles and Raster datahttps://doi.org/10.14509/31682Free download20250627Alaska 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"}