mhhw-shoreline: The present day shoreline (mean higher high water - MHHW) of the Sitka study area; see Grid Development and Data Sources section of this report to learn more about how this file was created. hypothetical-composite-line: Estimated, "maximum credible scenario" inundation line 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. hypothetical-composite-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. tectonic-scenario-01: Scenario 1. Multi-Segment event based on the JDM (PWS, KP, KI, and YY segments) tectonic-scenario-02: Scenario 2. Multi-Segment event based on the SDM (PWS, KP, KI, and YY segments) tectonic-scenario-03: Scenario 3. Modified multi-segment event: rupture of the PWS, KP, and YY segments of the JDM tectonic-scenario-04: Scenario 4. Modified multi-segment event: rupture of the PWS, KP, and YY segments of the SDM tectonic-scenario-05: Scenario 5. Multi-Segment event: the Tohoku-type rupture of the PWS, KP and KI segments tectonic-scenario-06: Scenario 6. The SAFRR tsunami scenario (SEM and SH segments) >tectonic-scenario-07: Scenario 7. Rupture in the Eastern Aleutians, from Semidi Islands to Fox Islands (SEM, SH, UN and FOX segments) tectonic-scenario-08: Scenario 8. Rupture on the Cascadia subduction zone >tectonic-scenario-09: Scenario 9. Mw8.2 thrust earthquake in the Haida Gwaii area
Suleimani, E.N., Nicolsky, D.J., and Koehler, R.D., 2013, Tsunami inundation maps of Sitka, Alaska: Report of Investigation RI 2013-3, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
This is a vector data set.
The horizontal datum used is World Geodetic System of 1984.
The ellipsoid used is World Geodetic System of 1984.
The semi-major axis of the ellipsoid used is 6378137.
The flattening of the ellipsoid used is 1/298.257223563.
This project was supported by the National Oceanic and Atmospheric Administration grants 27-014d and 06-028a through the Cooperative Institute for Arctic Research. 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 as part of the US Department of Defense HPC Modernization Program. We thank Dr. Lucinda Leonard and an anonymous reviewer for their thoughtful reviews of the draft manuscript and maps.
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Large seismic events occurring in the vicinity of the Alaska Peninsula, Aleutian Islands, and Gulf of Alaska have a very high potential for generating both local and Pacific-wide tsunamis. Saving lives and property depends on how well a community is prepared, which makes it essential to estimate the potential flooding of the coastal zone in the case of a local or distant tsunami. The Alaska Tsunami Mapping Team (ATMT) participates in the National Tsunami Hazard Mitigation Program (NTHMP) by evaluating and mapping potential inundation of selected parts of the Alaska coastline using numerical modeling of tsunami wave dynamics. The communities are selected for inundation modeling in coordination with the Division of Homeland Security and Emergency Management (DHSEM) with consideration for location, infrastructure, availability and quality of bathymetric and topographic data, and community involvement. The Sitka tsunami inundation maps described in the associated manuscript represent the results of the continuous effort of state and federal agencies to produce inundation maps for many Alaska coastal communities.
Hickman, P.J., Suleimani, E.N., and 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, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Lim, E., Eakins, B.W., and Wigley, R., 2011, Coastal relief model of southern Alaska: Procedures, data sources and analysis: NOAA Technical Memorandum NESDIS NGDC-43, National Geophysical Data Center, Marine Geology and Geophysics Division, United States.
Nicolsky, D.J, Suleimani, E.N, and Hansen, R.A, 2011, Validation and verification of a numerical model for tsunami propagation and runup: Pure and Applied Geophysics v. 168, Birkhauser Geoscience, Switzerland.
NOAA/NWS, 2012, National Tsunami Warning Center: National Oceanic and Atmospheric Administration, United States.
NOAA/WDS, 2012, Tsunami Event Database: National Oceanic and Atmospheric Administration, United States.
Data sources used in this process:
Data sources used in this process:
Data sources used in this process:
Nicolsky, D.J., Suleimani, E.N., Haeussler, P.J., Ryan, H.F., Koehler, R.D., Combellick, R.A., and Hansen, R.A., 2013, Tsunami inundation maps of Port Valdez, Alaska: Report of Investigation RI 2013-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Nicolsky, D.J., Suleimani, E.N., Combellick, R.A., and Hansen, R.A., 2011, Tsunami inundation maps of Whittier and western Passage Canal, Alaska: Report of Investigation RI 2011-7, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Suleimani, E.N., Combellick, R.A., Marriott, D., Hansen, R.A., Venturato, A.J., and Newman, J.C., 2005, Tsunami hazard maps of the Homer and Seldovia areas, Alaska: Report of Investigation RI 2005-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Suleimani, E.N., Hansen, R.A., Combellick, R.A., and Carver, G.A., 2002, Tsunami hazard maps of the Kodiak area, Alaska: Report of Investigation RI 2002-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Suleimani, E.N., Nicolsky, D.J., West, D.A., Combellick, R.A., and Hansen, R.A., 2010, Tsunami inundation maps of Seward and northern Resurrection Bay, Alaska: Report of Investigation RI 2010-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
The presented maps have been completed using the best information available and are believed to be accurate; however, their preparation required many assumptions. We have considered several tsunami scenarios and have provided an estimate of maximum credible tsunami inundation. Actual conditions during a tsunami event may vary from those considered, so the accuracy cannot be guaranteed. Landslide tsunami sources are not included in the current study due to unknown potential impact of such events on Sitka. The limits of inundation shown should only be used as a guideline for emergency planning and response action. Actual areas inundated will depend on specifi cs of earth deformations, on-land construction, and tide level, and may differ from areas shown on the map. The information on this map 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. Users should review the accompanying report, particularly the Sources of Errors and Uncertainties section, for a detailed discussion of limitations of the methods used to generate the various inundation models.
The extent of tsunami inundation was calculated through numerical modeling of water waves over bathymetry and topography. To efficiently compute a detailed map of potential tsunami inundation, we employed a series of nested computational grids. A nested grid allows for higher resolution in areas where it is needed, without expending computer resources in areas where it is not. The computational grid was based on digital elevation models (DEMs) obtained from various U.S. federal and academic agencies. The highest level of horizontal resolution of the grid used for inundation modeling is about 15 m (49 ft). This scale is mostly limited by the computational resources necessary to compute the tsunami inundation at the higher resolution. The 15 m (49 ft) resolution is high enough to describe major relief features, but small topographic features, buildings, and other facilities cannot be accurately resolved by the existing model. For additional information please reference the Grid Development and Data Sources section of the associated manuscript.
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.
The dataset contains calculated tsunami inundation limits for tectonic source scenarios. However, tsunamis caused by underwater slope failures are also a significant hazard in the fjords of coastal Alaska and other high-latitude fjord coastlines. Southeast Alaska has a long record of tsunami waves generated by submarine and subaerial landslides, avalanches, and rock falls. While we acknowledge that communities in southeastern Alaska are considered at risk from locally generated waves because of their proximity to landslide-prone fjords in a seismically active zone, we did not quantify this category of landslide tsunami hazard for Sitka in the current report due to poor constraints on the parameters of potential slides, such as locations, volumes, and geotechnical properties.
Results of numerical modeling were verified by simulating historic tsunamis. Inundation lines are visually inspected using GIS software for identification of anomalous elevations or data inconsistencies. See text report for detailed explanation of the tests used to determine the fidelity among the various data sources that were used to generate this dataset.
Are there legal restrictions on access or use of the data?
- 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.
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RI 2013-3
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.
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| Data format: | Vector data, Raster data |
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| Network links: |
<http://dx.doi.org/10.14509/26671> |
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