Earthquake Hazards 101 - the Basics  What is earthquake hazard?
Earthquake ground shaking varies from place to place and the
hazard mapping in this project will show this variability. The
mapped hazard refers to an estimate of the probability of
exceeding a certain amount of ground shaking, or ground motion,
in 50 years. The hazard depends on the magnitudes and locations
of likely earthquakes, how often they occur, and the properties
of the rocks and sediments that earthquake waves travel through.
What are hazard maps?  The National Hazard Maps show the
distribution of earthquake shaking levels that have a certain
probability of occurring in the United States. These maps were
created to provide the most accurate and detailed information
possible to assist engineers in designing buildings, bridges,
highways, and utilities that will withstand shaking from
earthquakes in the United States. These maps are used to create
and update the building codes that are now used by more than
20,000 cities, counties, and lo