How are earthquakes located and measured?

Knowing how fast seismic waves travel through the earth, seismologists can calculate the time when the earthquake occurred and its location by comparing the times when shaking was recorded at several stations. Earthquakes are recorded by a seismic network. Each seismic station in the network measures the movement of the ground at that site.

What are the chances an earthquake could hit your favorite locations? Make a One-Step Earthquake Forecast here.
To see locations of current major earthquakes, go the Hazards Viewer and click on one of the Earth globes on the right hand side.
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