Tsunami inundation maps for the city of Sand Point, Alaska

Staff from Alaska Earthquake Center, Geophysical Institute and Alaska Division of Geological & Geophysical Surveys evaluated potential tsunami hazards for the city of Sand Point, on Popof Island in the Shumagin Islands archipelago. We numerically modeled the extent of inundation from tsunami waves generated by local and distant earthquake sources. We considered the results in light of historical observations. The worst-case scenarios are defined by analyzing results of the sensitivity study of the tsunami dynamics with respect to different slip distributions along the Aleutian megathrust. For the Sand Point area, the worst-case scenarios are thought to be thrust earthquakes in the Shumagin Islands region with magnitudes ranging from Mw 8.8 to Mw 9.0. We additionally consider a Mw 9.0 rupture between Shumagin Islands and Kodiak Island, a Mw 9.0 rupture of the Cascadia subduction zone, and a Mw 8.6 outer-rise rupture in the area of the Shumagin Islands. Conducted numerical experiments reveal that a tsunami might start to arrive to Sand Point in about 15 minutes after the earthquake with a strong positive wave reaching in 1 hour the height of 7-8 m (23-26 ft) with respect to the pre-earthquake sea level. Consecutive waves might have the same of height or even be higher. The highest predicted wave height is 12-14 m (39-46 ft); a vertical difference between the trough and crest could be as much as 16 m (53 ft) and a time period between the water withdrawal and runup could be as short as 15 minutes. At least three devastating waves can reach the community in the first 2.5 hours after the earthquake. The first wave may not be the highest; the later waves might be more damaging and produce larger inundation. Results from the numerical modeling are intended to provide guidance to local emergency management agencies in tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards. Users can access the complete report and digital data from the DGGS website: http://doi.org/10.14509/29706.

Data and Resources

Field Value
access_constraints ["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.", "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)."]
bbox-east-long -160.462593
bbox-north-lat 55.370603
bbox-south-lat 55.276042
bbox-west-long -160.551594
contact-email dggspubs@alaska.gov
coupled-resource []
dataset-reference-date [{"type": "publication", "value": "2017-01-01"}]
frequency-of-update notPlanned
licence ["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."]
metadata-date 2017-11-30
metadata-language eng; USA
metadata_type geospatial
progress completed
resource-type dataset
responsible-party [{"name": "Alaska Division of Geological & Geophysical Surveys", "roles": ["pointOfContact"]}]
spatial {"type": "Polygon", "coordinates": [[[-160.551594, 55.276042], [-160.462593, 55.276042], [-160.462593, 55.370603], [-160.551594, 55.370603], [-160.551594, 55.276042]]]}
spatial_harvester true
temporal-extent-begin 2013-01-01
temporal-extent-end 2017-01-01
Groups
  • AmeriGEOSS
  • National Provider
  • North America
Tags
  • active-fault
  • alaska-earthquake-1964
  • aleutian-islands
  • amerigeo
  • amerigeoss
  • bathymetry
  • ckan
  • coastal
  • coastal-and-river
  • earthquake
  • emergency-preparedness
  • engineering
  • engineering-geology
  • fault-displacement
  • faulting
  • faults
  • flood
  • geo
  • geologic-hazards
  • geology
  • geoss
  • hazards
  • holocene
  • humboldt-harbor
  • inundation
  • land-subsidence
  • modeling
  • national
  • north-america
  • popof-island
  • raster-image
  • sand-point
  • seismic-gap
  • seismic-hazards
  • seismology
  • shumagin-islands
  • surface
  • topography
  • tsunami
  • united-states
  • water
isopen False
metadata_created 2025-11-21T05:12:35.958262
metadata_modified 2025-11-21T05:12:35.958267
notes Staff from Alaska Earthquake Center, Geophysical Institute and Alaska Division of Geological & Geophysical Surveys evaluated potential tsunami hazards for the city of Sand Point, on Popof Island in the Shumagin Islands archipelago. We numerically modeled the extent of inundation from tsunami waves generated by local and distant earthquake sources. We considered the results in light of historical observations. The worst-case scenarios are defined by analyzing results of the sensitivity study of the tsunami dynamics with respect to different slip distributions along the Aleutian megathrust. For the Sand Point area, the worst-case scenarios are thought to be thrust earthquakes in the Shumagin Islands region with magnitudes ranging from Mw 8.8 to Mw 9.0. We additionally consider a Mw 9.0 rupture between Shumagin Islands and Kodiak Island, a Mw 9.0 rupture of the Cascadia subduction zone, and a Mw 8.6 outer-rise rupture in the area of the Shumagin Islands. Conducted numerical experiments reveal that a tsunami might start to arrive to Sand Point in about 15 minutes after the earthquake with a strong positive wave reaching in 1 hour the height of 7-8 m (23-26 ft) with respect to the pre-earthquake sea level. Consecutive waves might have the same of height or even be higher. The highest predicted wave height is 12-14 m (39-46 ft); a vertical difference between the trough and crest could be as much as 16 m (53 ft) and a time period between the water withdrawal and runup could be as short as 15 minutes. At least three devastating waves can reach the community in the first 2.5 hours after the earthquake. The first wave may not be the highest; the later waves might be more damaging and produce larger inundation. Results from the numerical modeling are intended to provide guidance to local emergency management agencies in tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards. Users can access the complete report and digital data from the DGGS website: http://doi.org/10.14509/29706.
num_resources 12
num_tags 41
title Tsunami inundation maps for the city of Sand Point, Alaska