Colors on this map show the levels of horizontal shaking that have a 2-in-100 chance of being
exceeded in a 50-year period. Shaking is expressed as a percentage of g (g is the acceleration
of a falling object due to gravity).

For a Fact Sheet on 2008 United States National Seismic Hazard Maps
http://pubs.usgs.gov/fs/2008/3018/