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Seismic Hazard Map for the United States
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Frequently-anticipated questions:
- Title: Seismic Hazard Map for the United States
- Abstract:
-
This map layer shows seismic hazard in the United States. The data
represent a model showing the probability that ground motion will reach a
certain level. This map layer shows peak horizontal ground acceleration
(the fastest measured change in speed, for a particle at ground level that
is moving horizontally due to an earthquake) with a 10% probability of
exceedance in 50 years. Values are given in %g, where g is acceleration
due to gravity, or 9.8 meters/second^2. The lines of equal hazard, which
are the lines between the polygons, were determined by interpolating from
a grid of equally spaced points in latitude and longitude. Each point was
weighted based on the seismic hazard at that location. The grid spacing
is 0.1 degrees for Alaska and the conterminous United States, and 0.02
degrees for Hawaii.
- Supplemental_Information:
-
This map layer was prepared by combining spatially-smoothed historic
seismicity information with information from fault-specific sources. The
acceleration values contoured are the random horizontal component. The
reference site condition is firm rock, defined as having an average shear-
wave velocity of 760 meters/second in the top 30 meters corresponding to
the boundary between National Earthquake Hazards Reduction Program (NEHRP)
site classes B and C.
For more information about the USGS National Seismic Hazard Maps, please
visit <http://earthquake.usgs.gov/research/hazmaps/index.php>.
A description of how the underlying geologic and geophysical data
were prepared as well as the methodology used in calculating seismic
hazard for a geographic location can be found in the following reports:
Frankel, A., C. Mueller, T. Barnhard, D. Perkins, E.V. Leyendecker, N.
Dickman, S. Hanson, and M. Hopper, 1996, National Seismic-Hazard Maps:
Documentation June 1996: U.S. Geological Survey Open-File Report 96-532,
110 p.
Klein, F.W., A.D. Frankel, C.S. Mueller, R.L. Wesson and P.G. Okubo, 2001,
Seismic Hazard in Hawaii: high rate of large earthquakes and probabilistic
ground motion maps, Bulletin of the Seismological Society of America,
v. 91, pp. 479-498.
Petersen, M., W. Bryant, C. Cramer, T. Cao, M. Reichle, A. Frankel, J.
Lienkaemper, P. McCrory, and D. Schwartz, 1996, Probabilistic Seismic
Hazard Assessment for the State of California: California Division of
Mines and Geology Open-File Report 96-08, 66 p., and U.S. Geological
Survey Open-File Report 96-706, 66 p.
Wesson, Robert, Arthur Frankel, Charles Mueller, and Stephen Harmsen,
1999, Probabilistic Seismic Hazard Maps of Alaska: U.S. Geological Survey
Open-File Report 99-36, 48 p.
- How should this data set be cited?
Rukstales, Kenneth S. (compiler), 200208, Seismic Hazard Map for the United States: National Atlas of the United States, Reston, VA.
Online Links:
- What geographic area does the data set cover?
- West_Bounding_Coordinate: 172
- East_Bounding_Coordinate: -66
- North_Bounding_Coordinate: 72
- South_Bounding_Coordinate: 18
- What does it look like?
- Does the data set describe conditions during a particular time period?
- Calendar_Date: 2002
- Currentness_Reference: Publication date
- What is the general form of this data set?
- Geospatial_Data_Presentation_Form: Map
- How does the data set represent geographic features?
- How are geographic features stored in the data set?
This is a Vector data set.
It contains the following vector data types (SDTS terminology):
- GT-polygon composed of chains (3359)
- 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 0.000278.
Longitudes are given to the nearest 0.000278.
Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is GRS1980.
The semi-major axis of the ellipsoid used is 6378137.0.
The flattening of the ellipsoid used is 1/298.257222.
- How does the data set describe geographic features?
- Areas of equal seismic hazard (described by seihazp020.dbf).
- Areas of predicted peak horizontal ground acceleration within the
specified range, with a 10% probability of exceedance in 50 years.
(Source: U.S. Geological Survey)
- Shape
- The representation of the entity in the data.
(Source: National Atlas of the United States)
Value | Definition |
Polygon | 2-dimensional element
|
- Area
- The size of the shape in coverage units.
(Source: National Atlas of the United States)
Range of values |
Minimum: | 0.00000 |
Maximum: | 116.59068 |
- Perimeter
- The perimeter of the shape in coverage units.
(Source: National Atlas of the United States)
Range of values |
Minimum: | 0.00105 |
Maximum: | 192.55132 |
- Seihazm020
- Internal feature number.
(Source: National Atlas of the United States)
Range of values |
Minimum: | 2 |
Maximum: | 3360 |
- Acc_val
- The minimum peak horizontal ground acceleration value for the polygon,
as percent of gravity (9.8 meters/second2). Valid values are 0, 1, 2,
3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 60, 80, and 100.
(Source: National Atlas of the United States)
Range of values |
Minimum: | 0 |
Maximum: | 100 |
- Valley
- A code indicating whether the polygon represents a local minima.
(Source: U.S. Geological Survey)
Value | Definition |
0 | The polygon is not a local minima.
|
1 | The polygon is a local minima.
|
- Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
- Rukstales, Kenneth S. (compiler)
- Who also contributed to the data set?
- To whom should users address questions about the data?
Ken Rukstales
U.S. Geological Survey
Box 25046, Mail Stop 966
Denver, CO 80225
USA
303-273-8677 (voice)
303-273-8600 (FAX)
[email protected]
- Contact_Instructions: Please contact via e-mail or telephone
This map summarizes the quantitative information, available from geologic
and geophysical sources, about seismic ground motion hazard in the United
States. The data are intended for geographic display and analysis at the
national level, and for large regional areas. The data should be
displayed and analyzed at scales appropriate for 1:2,000,000-scale data.
No responsibility is assumed by the U.S. Geological Survey or the National
Atlas of the United States in the use of these data.
- From what previous works were the data drawn?
- SH-USA (source 1 of 3)
-
Frankel, A., Mueller, C., Barnhard, T., Perkins, D., Leyendecker, E.V., Dickman, N., Hanson, S., and Hopper, M., 1997, Seismic-Hazard Maps for the Conterminous United States: U.S. Geological Survey Open File Reports 97-131, U.S. Geological Survey, Reston, VA.
- Other_Citation_Details: 12 sheets
- Type_of_Source_Media: Paper
- Source_Scale_Denominator: 7000000
- Source_Contribution:
-
The publication describes the conterminous United States historical
seismicity and fault-specific sources used to build the theoretical
model, as well as the methodology employed.
- SH-Hawaii (source 2 of 3)
-
Klein, F.W., Frankel, A.D., Mueller, C.S., Wesson, R.L., and Okubo, P.G., 2000, Seismic-Hazard Maps for Hawaii: U.S. Geological Survey Geologic Investigations Series Map I-2724, U.S. Geological Survey, Reston, VA.
- Other_Citation_Details: 2 sheets
- Type_of_Source_Media: Paper
- Source_Scale_Denominator: 2000000
- Source_Contribution:
-
The publication describes the Hawaiian historical seismicity and fault-
specific sources used to build the theoretical model, as well as the
methodology employed.
- SH-Alaska (source 3 of 3)
-
Wesson, R., Frankel, A., Mueller, C., and Harmsen, S., 1999, Seismic-Hazard Maps for Alaska and the Aleutian Islands: U.S. Geological Survey Geologic Investigations Series Map I-2679, U.S. Geological Survey, Reston, VA.
- Other_Citation_Details: 2 sheets
- Type_of_Source_Media: Paper
- Source_Scale_Denominator: 7500000
- Source_Contribution:
-
The publication describes the Alaskan and Aleutian historical
seismicity and fault-specific sources used to build the theoretical
model, as well as the methodology employed.
- How were the data generated, processed, and modified?
- Date: 2002 (process 1 of 1)
-
Information drawn from the sources was used to produce an ASCII file
of grid points having a latitude and longitude spacing of either 0.1
degrees (conterminous United States and Alaska) or 0.02 degrees
(Hawaii). For each grid point an associated acceleration value, or
weight, was calculated from the historic seismicity and fault-specific
sources, according to the prescribed seismological model. The data were
then contoured using Arc/INFO. The desired final lines of equal
seismological hazard were selected and polygon and arc topology were
ascertained as well as appropriate feature attributes. The file was
converted to Shapefile format.
Person who carried out this activity:
Ken Rukstales
U.S. Geological Survey
Box 25046, Mail Stop 966
Denver, Colorado 80225
USA
303-273-8677 (voice)
303-273-8600 (FAX)
[email protected]
- Contact_Instructions: Please contact via e-mail or telephone
- What similar or related data should the user be aware of?
Frankel, A., Mueller, C., Barnhard, T., Perkins, D., Leyendecker, E.V., Dickman, N., Hanson, S., and Hopper, M., 1997, Seismic-Hazard Maps for California, Nevada and Western Arizona/Utah: U.S. Geological Survey Open File Reports 97-130, U.S. Geological Survey, Reston, VA.
- Other_Citation_Details: 12 sheets, scale 1:2,000,000
Frankel, A., Mueller, C., Barnhard, T., Perkins, D., Leyendecker, E.V., Dickman, N., Hanson, S., and Hopper, M., 1997, Seismic-Hazard Maps for the Conterminous United States: U.S. Geological Survey Open File Reports 97-131, U.S. Geological Survey, Reston, VA.
- Other_Citation_Details: 12 sheets, scale 1:7,000,000
Klein, F.W., Frankel, A.D., Mueller, C.S., Wesson, R.L., and Okubo, P.G., 2000, Seismic-Hazard Maps for Hawaii: U.S. Geological Survey Geologic Investigations Series Map I-2724, U.S. Geological Survey, Reston, VA.
- Other_Citation_Details: 2 sheets, scale 1:2,000,000
Wesson, R., Frankel, A., Mueller, C., and Harmsen, S., 1999, Seismic-Hazard Maps for Alaska and the Aleutian Islands: U.S. Geological Survey Geologic Investigations Series Map I-2679, U.S. Geological Survey, Reston, VA.
- Other_Citation_Details: 2 sheets, scale 1:7,500,000
- How well have the observations been checked?
This map layer is based on a theoretical model. The following resources
provide information on quality assessment for the map layer:
Frankel, A., C. Mueller, T. Barnhard, D. Perkins, E.V. Leyendecker, N.
Dickman, S. Hanson, and M. Hopper, 1996, National Seismic-Hazard Maps:
Documentation June 1996: U.S. Geological Survey Open-File Report
96-532, 110 p.
Klein, F.W., A.D. Frankel, C.S. Mueller, R.L. Wesson, and P.G. Okubo,
2001, Seismic Hazard in Hawaii: high rate of large earthquakes and
probabilistic ground motion maps, BSSA v. 91, pp. 479-498.
Petersen, M., W. Bryant, C. Cramer, T. Cao, M. Reichle, A. Frankel, J.
Lienkaemper, P. McCrory, and D. Schwartz, 1996, Probabilistic Seismic
Hazard Assessment for the State of California: California Division of
Mines and Geology Open-File Report 96-08, 66 p., and U.S. Geological
Survey Open-File Report 96-706, 66 p.
Wesson, Robert, Arthur Frankel, Charles Mueller, and Stephen Harmsen,
1999, Probabilistic Seismic Hazard Maps of Alaska: U.S. Geological Survey
Open-File Report 99-36, 48 p.
- How accurate are the geographic locations?
The location of features is based on theoretical calculations of a
seismological model for the study area. The location of each point
is considered to be correct within the confines of computer accuracy.
- How accurate are the heights or depths?
- Where are the gaps in the data? What is missing?
This map layer shows levels of seismic hazard for the United States.
- How consistent are the relationships among the observations, including topology?
Polygon and chain-node topology are present.
Uncertainty in the underlying seismicity or fault parameters was not
considered in the production of this map layer.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None.
- Use_Constraints:
-
Acknowledgment of the National Atlas of the United States of America and
(or) the U.S. Geological Survey, National Seismic Hazard Mapping Project
would be appreciated in products derived from these data.
- Who distributes the data set? (Distributor 1 of 1)
Earth Science Information Center, U.S. Geological Survey
507 National Center
Reston, VA 20192
1-888-ASK-USGS (1-888-275-8747) (voice)
- Contact_Instructions:
-
In addition to the address above there are other ESIC offices
throughout the country. A full list of these offices is at
<http://ask.usgs.gov/esic_index.html>.
- What's the catalog number I need to order this data set?
- What legal disclaimers am I supposed to read?
Although these data have been processed successfully on a computer system
at the U.S. Geological Survey, no warranty expressed or implied is made by
the U.S. Geological Survey regarding the utility of the data on any other
system, nor shall the act of distribution constitute any such warranty.
No responsibility is assumed by the U.S. Geological Survey in the use of
these data.
- How can I download or order the data?
- Availability in digital form:
- Cost to order the data: There is no charge for the map layer.
- Dates:
- Last modified: 09-Aug-2006
- Metadata author:
-
Peg Rawson
National Atlas of the United States
12201 Sunrise Valley Dr
Reston, VA 20192
USA
703-648-4183 (voice)
[email protected]
- Metadata standard:
- FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
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