Identification_Information: Citation: Citation_Information: Originator: Rukstales, Kenneth S. (compiler) Publication_Date: 201201 Title: Seismic Hazard Map for the United States Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Reston, VA Publisher: National Atlas of the United States Online_Linkage: Description: 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, 0.05 degrees for the conterminous United States, and 0.02degrees for Hawaii. Purpose: 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. 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 100 Enumerated_Domain_Value_Definition: Acceleration values within the polygon have values >= 100% g Enumerated_Domain_Value_Definition_Source: USGS Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Earth Science Information Center, U.S. Geological Survey Contact_Address: Address_Type: Mailing address Address: 507 National Center City: Reston State_or_Province: VA Postal_Code: 20192 Contact_Voice_Telephone: 1-888-ASK-USGS (1-888-275-8747) Contact_Voice_Telephone: 703-648-5920 Contact_Instructions: In addition to the address above there are other ESIC offices throughout the country. A full list of these offices is at . Distribution_Liability: 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ESRI Shapefile Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: Digital_Form: Digital_Transfer_Information: Format_Name: SDTS Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: Fees: There is no charge for the map layer. Metadata_Reference_Information: Metadata_Date: 20120118 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Peg Rawson Contact_Organization: National Atlas of the United States Contact_Address: Address_Type: Mailing address Address: 12201 Sunrise Valley Dr Address: MS 561 City: Reston State_or_Province: VA Postal_Code: 20192 Country: USA Contact_Voice_Telephone: 703-648-4183 Contact_Electronic_Mail_Address: atlasmail@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Security_Information: Metadata_Security_Classification_System: None Metadata_Security_Classification: Unclassified Metadata_Security_Handling_Description: None