Maximum tsunami wave height with 0.2 or 1 percent annual probability of exceedance, Seaside, Oregon (exrate)

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Frequently-anticipated questions:

What does this data set describe?

Title:
Maximum tsunami wave height with 0.2 or 1 percent annual probability of exceedance, Seaside, Oregon (exrate)
Abstract:
Probabilistic tsunami hazard assessment analysis (PTHA) was used to develop 100- and 500-year flood maps at Seaside, Oregon. This data set consists of contours of maximum wave height (referenced to MHHW) with a probabilities of 0.010 or 0.002 (1 or 0.2 percent chance) of being exceeded in any given year. These are commonly referred to as the 100- and 500-year floods, respectively, although it should be noted that tsunamis and the causative earthquakes are highly aperiodic.
Supplemental_Information:
Data sets covered by this metadata document have prefixes exrate010 and exrate002 for 1 and 0.2 percent probability of exceedance, respectively.

exrate010.shp, exrate002.shp - PTHA wave heights determined by input from all far- and near-field sources

exrate002c.shp - smoothed version of exrate002.shp

exrate010aa.shp, exrate002aa.shp - wave heights determined using only source 1 of the Alaska-Aleutian segmentation

exrate010td480.shp, exrate002td480.shp - PTHA wave heights determined using a mean inter-event time of 480 years (mean value from records)

exrate010td560.shp, exrate002td560.shp - PTHA wave heights determined using a mean inter-event time of 560 years (value from model)

Although the 100-year probabilistic inundation (exrate010) looks similar to inundation from the historic 1964 event, the 100-year probabilistic map is the aggregate of many different tsunami sources around the Pacific. From the little data available, the mean inter-event time for a 1964-type earthquake in Alaska is quite long (~750 years), although again, earthquakes are highly aperiodic.

The 500-year probabilistic map (exrate002) is dominated by Cascadia earthquakes, but because the average inter-event time is thought to be greater than 500 years for a Cascadia M~9 earthquake, the wave heights in the 500-year probabilistic map are slightly less than for a given Cascadia scenario.

  1. How should this data set be cited?

    Geist, Eric L. , and Wong, Florence L. , 2006, Maximum tsunami wave height with 0.2 or 1 percent annual probability of exceedance, Seaside, Oregon (exrate):.

    Online Links:

    This is part of the following larger work.

    Wong, Florence L. , Venturato, Angie J. , and Geist, Eric L. , 2006, Seaside, Oregon Tsunami Pilot Study - Modernization of FEMA Flood Hazard Maps: GIS Data: U.S. Geological Survey Data Series 236, U.S. Geological Survey, Menlo Park, California.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -123.969688
    East_Bounding_Coordinate: -123.910658
    North_Bounding_Coordinate: 46.059678
    South_Bounding_Coordinate: 45.968825

  3. What does it look like?

    <https://pubs.usgs.gov/ds/2006/236/metadata/exrate.gif> (GIF)
    Maximum tsunami wave heights with annual probabilities of exceedance of 0.010 and 0.002

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 2006
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • String (65)
      • Point (4)

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0003. Longitudes are given to the nearest 0.0003. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    exrate010
    arc attribute table (Source: ESRI)

    LENGTH
    Length of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    MAXWVHT_M
    maximum wave height in meters referenced to MHHW (Source: Tsunami Pilot Study Working Group, 2006)

    Ranges indeterminate.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Entity_and_Attribute_Overview:
    Contours of maximum wave heights for tsunamis with 1 or 0.2 percent annual probability of occurrence in the Seaside, Oregon, area
    Entity_and_Attribute_Detail_Citation: Tsunami Pilot Study Working Group, 2006

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Florence L. Wong
    U.S. Geological Survey
    Geologist
    345 Middlefield Road, MS 999
    Menlo Park, California 94025
    USA

    650-329-5327 (voice)
    650-329-5190 (FAX)
    fwong@usgs.gov

Why was the data set created?

This data set is one of a collection of digital files of a geographic information system of spatially referenced data related to the Seaside, Oregon, Tsunami Pilot Study.

Federal Emergency Management Agency (FEMA) Federal Insurance Rate Map (FIRM) guidelines do not currently exist for conducting and incorporating tsunami hazard assessments that reflect the substantial advances in tsunami research achieved in the last two decades (Tsunami Pilot Study Working Group, 2006). Therefore, as part of FEMAs Modernization Program, a Tsunami Pilot Study was carried out in the Seaside/Gearhart, Oregon, area to provide information from which tsunami mapping guidelines could be developed. This area was chosen because it is typical of coastal communities in the section of the Pacific Coast from Cape Mendocino to the Strait of Juan de Fuca. There was also considerable interest shown by state agencies and local stakeholders in mapping the tsunami threat to this area. The study was an interagency effort by scientists from the U.S. Geological Survey, the National Oceanic and Atmospheric Administration, the University of Southern California, and the Middle East Technical University. We present the GIS data from that report in this publication.

These data are intended for science researchers, students, policy makers, and the general public. The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 2005 (process 1 of 1)
    The results of the probabilistic tsunami hazard analysis (PTHA) are grids of probability values for a series of tsunami wave heights in 0.5-m increments from 0.5 m to 10.5 m (Tsunami Pilot Study Working Group, 2006). The cell size is defined by the near-field tsunami source models and is 0.000558 degree in geographic coordinates or approximately 60 m in projected coordinates. The cell values were exported from PTHA as xyz (longitude, latitude, probability) values and reformatted as ArcGIS grids. The grid for each wave height (e.g., iy01_005g) was contoured with an interval of 0.2% or 0.002 probability. The 1.0% contours for each wave height were merged into one file (exrate010) representing an annual probability of exceedance of 1.0% or the 100-year tsunami (Wong, 2006). Similarly the 0.2% contours were compiled as exrate002. The 0.2% data were further smoothed to resolve sub-gridcell data overlaps and are presented in exrate002c.

  3. What similar or related data should the user be aware of?

    TPSWG Tsunami Pilot Study Working Group, 2006, Seaside, Oregon Tsunami Pilot Study - Modernization of FEMA Flood Hazard Maps: U.S. Geological Survey Open-File Report 2006-1234, U.S. Geological Survey, Menlo Park, California.

    Online Links:

    Geist, Eric L. , and Parsons, Tom, 2006, Probabilistic analysis of tsunami hazards: Natural Hazards v. 37, n. 3, p. 277-314.

    Wong, Florence L. , 2006, Surface and Area Calculation for the 100-year and 500-year Floods, Appendix G:.

    This is part of the following larger work.

    Tsunami Pilot Study Working Group, 2006, Seaside, Oregon Tsunami Pilot Study - Modernization of FEMA Flood Hazard Maps: U.S. Geological Survey Open-File Report 2006-1234, California, Menlo Park.

    Online Links:

    Mofjeld, H.O., Venturato, A.J., González, F.I., 2004, Background tides and sea level variations at Seaside, Oregon: NOAA, Technical Memorandum OAR PMEL-126.

    Online Links:

    Other_Citation_Details: 15 pages
    Geist, Eric L. , 2005, Local Tsunami Hazards in the Pacific Northwest from Cascadia Subduction Zone Earthquakes: U.S. Geological Survey Professional Paper 1661-B.

    Online Links:

    Other_Citation_Details: 21 pages

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    The maximum wave heights presented here were modeled by probabilistic tsunami hazard assessment techniques and approximate the magnitudes of a 1% annual probability flood. Accuracy with these estimates can be associated with uncertainty in the model results. Sources of aleatory uncertainty from fault rupture complexity and tidal stage at tsunami arrival time. For the former, the coefficient of variation is typically 20% (Geist, 2005). For the latter, the coefficient of variation is typically 7% (Mofjeld and others, 2004). A comprehensive analysis for other sources of aleatory and epistemic uncertainty has not been conducted for this pilot study.

  2. How accurate are the geographic locations?

    The model was constructed on a 2-second grid spacing (approximately 60 meters north-south). All model wave height and probability calculations are referenced to this grid.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    Complete.

  5. How consistent are the relationships among the observations, including topology?

    No tests of logical consistency were conducted.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None.
Use_Constraints:
Annual probability of exceedance for different total wave heights, including tides, were specifically developed for the FEMA tsunami pilot study probability specifications (see umbrella Use Constraint). This dataset should not be used for any other purpose, including other insurance applications.

The data, digital results, GIS layers, and map products in this database have been created specifically as part of a pilot study for FEMA's modernization of Flood Insurance Rate Maps (FIRMs) project. The results of the pilot study are intended to help FEMA draft new guidelines related to tsunami flooding for Coastal Flood Hazard Analysis and Mapping for the Pacific Coast of the United States. The results are intrinsically probabilistic and designed according to FEMA flood zone specifications: annual probabilities of exceedance of 1% and 0.2%. The data, digital results, GIS layers, and map products are not intended for other uses. In particular, the 1% and 0.2% annual exceedance probability tsunami flood maps are not to be used for emergency planning, evacuation, or other insurance purposes. Please refer to the National Tsunami Hazard Mitigation Program tsunami inundation maps for use in emergency planning.

Please recognize the U.S. Geological Survey (USGS) as the source of this information.

Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.

The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.

This information is not intended for navigational purposes.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey
    USGS Information Services
    Denver, Colorado 80225-0286
    USA

    1-888-275-8747 (voice)
    infoservices@usgs.gov

  2. What's the catalog number I need to order this data set?

    U.S. Geological Survey Data Series 236

  3. What legal disclaimers am I supposed to read?

    This information is not intended for navigational purposes.

    Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    Shapefile format is viewable with geographic information system (GIS) software.

Who wrote the metadata?

Dates:
Last modified: 10-Aug-2006
Metadata author:
U.S. Geological Survey
c/o Florence L. Wong
Geologist
345 Middlefield Road, MS 999
Menlo Park, California 94025
USA

650-329-5327 (voice)
650-329-5190 (FAX)
fwong@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.11 on Tue Dec 19 09:15:35 2006