Although earthquakes cannot be predicted, seismic activity can be monitored and particularly active regions can be measured. People think of major earthquakes such as those in California when they think of earthquakes, but in fact there is seismic activity across the nation. In fact, 500,000 earthquakes occur each year, with 100,000 strong enough to be felt.
The United States Geological Survey (USGS), an arm of the the Department of the Interior, measures earthquakes and activity and provides information on earthquake-prone regions, as well as potential tsunami activity. USGS also provides the public with information about safety during and after an earthquake.