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Earthquakes: The Deadly Tremor
Works Cited | Plates of the Earth | What causes an Earthquake? | The Four Layers of the Earth

Welcome to the site about earthquakes! Here you will learn all about earthquakes and what causes them.

Some earthquakes can be very catastrophic, but others can cause very little damage. Earthquakes are caused by tectonic plates colliding with each other to move the ocean floor, continents, etc.

 damage done by an earthquake

Seismologists are people who study earthquakes. They use the facts to find out the epicenter of an earthquake. They utilize the time it occured, the difference between the P and S waves from three different stations among other things to find out the origin of the earthquake.

What are P and S waves?

The P wave stands for primary wave while the S wave stands for secondary wave. The P wave is the fastest seismic wave and the first you would feel during an earthquake. The S waves would be the second wave you would feel. Seismologists measure the P and S waves using a Seismograph. At the beginning of an earthquake the two tallest waves shown on the Seismograph are the P and S waves (P is the first the S is the second). Then they put the difference of arrival in seconds into this equation:
   difference in arrival times for P and S waves x 100
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That gives them the range in kilometers the earthquake reached around that station.
 

 This is an example of a seismograph.