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Once upon a time, seismologists could only measure an earthquake’s shaking. Today, they can study the minute details of Earth’s day-to-day movements using the Global Positioning System (GPS), which is accurate to the millimeter.
GPS Technology
Twenty four satellites orbiting Earth radio data about their location to receivers on the ground. The amount of time it takes for the signals to reach the receiver is used to determine the receiver’s position.
With strategically placed receivers, scientists can use GPS data to measure even tiny movements along fault lines year-to-year, between earthquakes. They can also use GPS to estimate a quake’s magnitude by studying how much the ground moved at a fault when the quake happened.
Viewing Seismic Activity
Today, networks of hundreds of seismometers are at work around the world. They detect and measure more than 100,000 earthquakes every year, instantly transmitting data about location and magnitude to computers across the globe.
Continue to The 2004 Indian Ocean Tsunami. >>
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