Nicolsky, D.J.
Suleimani, E.N.
Freymueller, J.T.
Koehler, R.D.
2015
Tsunami inundation maps of Fox Islands communities, including Dutch Harbor and Akutan, Alaska
report and digital data
Report of Investigation
RI 2015-5
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
67 p., 2 sheets, scale 1:12,500.
http://dx.doi.org/10.14509/29414
Potential tsunami hazards for the Fox Islands communities of Unalaska/Dutch Harbor and Akutan were evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources and taking into account historical observations. Worst-case hypothetical scenarios are defined by analyzing results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Aleutian megathrust. The worst-case scenarios for Unalaska and Akutan are thought to be thrust earthquakes in the Fox Islands region with magnitudes ranging from Mw 8.8 to Mw 9.1 that have their greatest slip at 30-40 km (18-25 mi) depth. We also consider Tohoku-type ruptures and an outer-rise rupture in the area of the Fox Islands. 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.
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.
>border: Outline of the study area.
>max-inundation-line: 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 line becomes a basis for local tsunami hazard planning and development of evacuation maps.
>max-flow-depth: Raster images depicting maximum composite flow depths over dry land. Pixel values provide the modeled depth (in meters) of maximum inundation. 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.
>time-series-points: To help emergency management personnel assess tsunami hazards, we supplement the inundation maps with the time series plots of the modeled water level and velocity dynamics at some on-land and some offshore locations in the communities. The plots are provided in the appendices of the report. These shapefiles provide the location of each time series point.
>scenarios: Shapefiles that depict the modeled potential maximum inundation by tectonic waves for each modeled scenario (scenarios 1-10). Detailed information about each scenario can be found in the accompanying report.
2015
publication date
None planned
-166.659760
-165.700483
54.157923
53.810076
ISO 19115 Topic Category
geoscientificInformation
Alaska Division of Geological & Geophysical Surveys
Active Fault
Coastal
Earthquake
Earthquake Related Slope Failure
Emergency Preparedness
Engineering
Engineering Geology
Fault Displacement
Faulting
Flood
Geologic Hazards
Geology
Hazards
Inundation
Land Subsidence
Landslide
Modeling
Raster Image
Seismic Gap
Seismic Hazards
Slides
Slope
Slope Instability
Tides
Topography
Tsunami
Alaska Division of Geological & Geophysical Surveys
Akutan
Fox Islands
Unalaska
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).
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 Surveys
GIS Manager
mailing and physical
3354 College Road
Fairbanks
AK
99709-3707
USA
(907)451-5020
dggsgis@alaska.gov
8 am to 4:30 pm, Monday through Friday, except State holidays
This project received support from the National Oceanic and Atmospheric Administration (NOAA) under Reimbursable Services Agreement ADN 0931000 with the State of Alaska's Division of Homeland Security & Emergency Management (a division of the Department of Military and Veterans Affairs). Some of the research in this publication is sponsored by the Cooperative Institute for Alaska Research with funds from NOAA under cooperative agreement NA08OAR4320751 with the University of Alaska Fairbanks. 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. We thank Zebulon Maharrey for his help with the RTK GPS survey in Unalaska/Dutch Harbor and Akutan and Amy Macpherson for her help with the cartography. We are grateful to Douglas Christensen and Natasha Ruppert for their help in assessing potential earthquakes in the Fox Islands and for sharing the data with us. Thoughtful reviews by Rob Witter (USGS, Alaska Science Center) and Hong Kie Thio (AECOM) improved the report.
Department of Public Safety, Unalaska
2015
Tsunami Inundation Zones and Evacuation Routes
last accessed October, 2015
http://www.ci.unalaska.ak.us/publicsafety/page/emergency-preparedness
Hickman, P.J.
Suleimani, E.N.
Nicolsky, D.J.
2012
Digital elevation model of Sitka Harbor and the city of Sitka, Alaska: Procedures, data sources, and quality assessment
Miscellaneous Publication
MP 144
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
38 p
http://dx.doi.org/10.14509/23964
Macpherson, A.E.
Nicolsky, D.J.
Suleimani, E.N.
2014
Digital elevation models of Skagway and Haines, Alaska: Procedures, data sources, and quality assessment
Miscellaneous Publication
MP 155
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
15 p
http://dx.doi.org/10.14509/29143
Nicolsky, D.J.
Suleimani, E.N.
Combellick, R.A.
Hansen, R.A.
2011
Tsunami inundation maps of Whittier and western Passage Canal, Alaska
Report of Investigation
RI 2011-7
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
65 p
http://dx.doi.org/10.14509/23244
Nicolsky, D.J.
Suleimani, E.N.
Haeussler, P.J.
Ryan, H.F.
Koehler, R.D.
Combellick, R.A.
Hansen, R.A.
2013
Tsunami inundation maps of Port Valdez, Alaska
Report of Investigation
RI 2013-1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
77 p., 1 sheet, scale 1:12,500
http://dx.doi.org/10.14509/25055
Nicolsky, D.J.
Suleimani, E.N.
Koehler, R.D.
2014
Tsunami inundation maps of Cordova and Tatitlek, Alaska
Report of Investigation
RI 2014-1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
49 p
http://dx.doi.org/10.14509/27241
Nicolsky, D.J.
Suleimani, E.N.
Koehler, R.D.
2014
Tsunami inundation maps of the villages of Chenega Bay and northern Sawmill Bay, Alaska
Report of Investigation
RI 2014-3
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
50 p
http://dx.doi.org/10.14509/29126
Nicolsky, D.J.
Wolken, G.J.
Combellick, R.A.
Hansen, E.
2011
APPENDIX B: Potential rockfall-generated tsunami at Whittier, Alaska
Report of Investigation
RI 2011-7A
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
p. 57-65
http://dx.doi.org/10.14509/23283
Simmons, Scott
Nelsen, Scott
2013
City of Unalaska hazard mitigation plan: U.S. Department of Homeland Security in cooperation with Alaska Division of Homeland Security and Emergency Management and URS Corporation
230 p.
http://www.ci.unalaska.ak.us/planning/page/planning-department-plans-policies
Suleimani, E.N.
Combellick, R.A.
Marriott, D.
Hansen, R.A.
Venturato, A.J.
Newman, J.C.
2005
Tsunami hazard maps of the Homer and Seldovia areas, Alaska
Report of Investigation
RI 2005-2
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
28 p., 2 sheets, scale 1:12,500
http://dx.doi.org/10.14509/14474
Suleimani, E.N.
Hansen, R.A.
Combellick, R.A.
Carver, G.A.
2002
Tsunami hazard maps of the Kodiak area, Alaska
Report of Investigation
RI 2002-1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
16 p., 4 sheets, scale 1:12,500
http://dx.doi.org/10.14509/2860
Suleimani, E.N.
Nicolsky, D.J.
West, D.A.
Combellick, R.A.
Hansen, R.A.
2010
Tsunami inundation maps of Seward and northern Resurrection Bay, Alaska
Report of Investigation
RI 2010-1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
47 p., 3 sheets, scale 1:12,500
http://dx.doi.org/10.14509/21001
Suleimani, E.N.
Nicolsky, D.J.
Koehler, R.D.
2013
Tsunami inundation maps of Sitka, Alaska
Report of Investigation
RI 2013-3
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
76 p., 1 sheet, scale 1:250,000
http://dx.doi.org/10.14509/26671
Suleimani, E.N.
Nicolsky, D.J.
Koehler, R.D.
2015
Tsunami inundation maps of Elfin Cove, Gustavus, and Hoonah, Alaska
Report of Investigation
RI 2015-1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
79 p
http://dx.doi.org/10.14509/29404
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. It has received technical review by several scientists familiar with the subject matter. Uncertainties associated with the depiction or interpretation of various features are discussed in the manuscript.
Model validation for this report included comparison of the modeled results to observations that were recorded during historic events.
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.
The hydrodynamic model used to calculate propagation and runup of tsunami waves is a nonlinear, flux-formulated, shallow-water model. It passes the validation and verification tests required for models used in production of tsunami inundation maps. The source mechanism remains the biggest unknown in the problem of tsunami modeling. Since the initial condition for the modeling is determined by the displacement of the ocean bottom, the largest source of error is the earthquake model. When the tsunami is generated in the vicinity of the coast, the direction of the incoming waves, their amplitudes and times of arrival are determined by the initial displacements of the ocean surface in the source area because the distance to the shore is too small for the waves to dissipate. Therefore, the near-field inundation modeling results are especially sensitive to the fine structure of the tsunami source. The modeling process is highly sensitive to errors when the complexity of the source function is combined with its proximity to the coastal zone. Additionally, during development of tsunami inundation maps a spatially-averaged ground subsidence/uplift model is assumed for Unalaska/Dutch Harbor and Akutan. However, during a potential earthquake, soil compaction in areas of unconsolidated deposits in the coastal zone might occur, and tsunami inundation could extend farther landward. Finally, we mention that the horizontal resolution of the grid used for inundation modeling is about 16 m (52 ft). This resolution is high enough to describe major relief features, but small topographic features, buildings, and other facilities cannot be resolved accurately by the existing model.
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. 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 Grid Development and Data Sources section of the associated manuscript.
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 Dutch Harbor and Akutan. 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 bathymetric and topographic relief in each nested grid is based on digital elevation models (DEMs) developed at the National Geophysical Data Center (NGDC) of the National Oceanic Atmospheric Administration (NOAA), in Boulder, Colorado. The extent of each grid used for our tsunami inundation mapping is listed in the accompanying report. To provide greater DEM accuracy near the shorelines, we augmented the topographic datasets with RTK - GPS survey measurements. Survey measurements were converted to MHHW datum using methods described within the associated report. See Methodology and Data section of the accompanying report for more detail and additional grid development source information.
2012
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 nonlinear shallow water equations using a finite-difference method on a staggered grid. See the accompanying report for more detail and additional model information.
2012
Model verification - We verified the numerical model by comparing results of the inundation modeling with observations collected from the Tohoku 2011 tsunami. First, we simulated the tectonic tsunami in Dutch Harbor and Akutan using an output of a coseismic deformation model of each of the earthquake as an initial condition for water waves. Then we compared the modeled inundation zones with the observed extent of inundation. See the accompanying report for more detail and additional model information.
2013
Numerical simulations of hypothetical tsunami scenarios - We assessed hazard related to tectonic tsunamis in Dutch Harbor and Akutan by performing model simulations for each hypothetical source scenario. Numerical results for each scenario include extent of inundation, sea level and velocity time series calculations, and tsunami flow depth. See the accompanying report for more detail and additional information.
2014
Compilation of maximum inundation zone and maximum flow depths - We calculated maximum composite extent of inundation by combining the maximum calculated inundation extents of all scenarios. The same method was used for calculation of maximum flow depths over dry land. See the accompanying report for more detail and additional information.
2015
Calculation of the potential inundation lines - For each grid cell in the high-resolution DEMs Dutch Harbor and Akutan, we determined whether the cell was inundated by waves or stayed dry throughout the entire simulation. Then, we defined a function such that it is equal to one at the center of each wet cell and is negative one at the center of each dry cell. Using a linear interpolation algorithm in Matlab, we plotted a zero-value contour that delineates dry and wet cells from each other. The resultant contour line (or a collection of lines if the contour is not a simply connected) was directly exported to the ArcGIS using WGS84 datum.
2015
.000001
.000001
decimal degrees
World Geodetic System of 1984
WGS 84
6378137
298.257223563
Mean Higher High Water
1
meter
Attribute values
ri2015-5-border.shp
Outline of the study area. File format: shapefile
Alaska Division of Geological & Geophysical Surveys (DGGS) and Alaska Earthquake Center, Geophysical Institute, University of Alaska
border
ri2015-5-max-inundation-line-akutan.shp,
ri2015-5-max-inundation-line-unalaska.shp
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 line becomes a basis for local tsunami hazard planning and development of evacuation maps. File format: shapefile
Alaska Earthquake Center, Geophysical Institute, University of Alaska, this report
max-inundation-line
ri2015-5-max-flow-depth-akutan.tif,
ri2015-5-max-flow-depth-unalaska.tif
Raster images depicting maximum composite flow depths over dry land. Pixel values provide the modeled depth (in meters) of maximum inundation. 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: GeoTIFF
Alaska Earthquake Center, Geophysical Institute, University of Alaska, this report
max-flow-depth
ri2015-5-time-series-points-akutan.shp,
ri2015-5-time-series-points-unalaska.shp
To help emergency management personnel assess tsunami hazards, we supplement the inundation maps with the time series plots of the modeled water level and velocity dynamics at some on-land and some offshore locations in the communities. The plots are provided in the appendices of the report. These shapefiles provide the location of each time series point. File format: shapefile
Alaska Earthquake Center, Geophysical Institute, University of Alaska, this report
time-series-points
ri2015-5-scenarios-akutan,
ri2015-5-scenarios-unalaska
Shapefiles that depict the modeled potential maximum inundation by tectonic waves for each modeled scenario (scenarios 1-10). Detailed information about each scenario can be found in the accompanying report. File format: shapefile
Alaska Earthquake Information Center, Geophysical Institute, University of Alaska, this report
scenarios
Alaska Division of Geological & Geophysical Surveys
mailing and physical
3354 College Road
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AK
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dggspubs@alaska.gov
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Please view our website (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.
RI 2015-5
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.
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.
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Shapefiles
http://dx.doi.org/10.14509/29414
Free download
20160112
Alaska Division of Geological & Geophysical Surveys
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mailing and physical
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Fairbanks
AK
99709-3707
USA
(907)451-5020
FGDC Content Standard for Digital Geospatial Metadata
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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.
http://www.dggs.alaska.gov/metadata/dggs.ext
dggs metadata extensions