Types of seismic waves created by an earthquake include P-waves and S-waves that travel throught the earth as well as surface waves, which can cause a lot of damage at the Earth's surface.
Courtesy of USGS
Seismic Waves: Moving and Shaking During an Earthquake
During an earthquake, the ground shakes making it difficult or impossible to stand up without falling. The land can also roll in waves Ė sinking in some places and rising in others. How does all this moving and shaking happen? During an earthquake, energy is released in seismic waves that travel outward from the center of the earthquake.
There are different types of seismic waves.† Each type of seismic wave has a special way of moving.
Some seismic waves can travel deep within the Earth. These are called body waves.
- One type of body wave is very fast. As it travels rock is squished together and then stretched apart over and over again. It can travel through solid rock and molten liquid layers of the Earth.
- The other type of body wave is slower and rock is shifted up and down or side to side as it travels foreword. This type of seismic wave can only travel through solid rock.
Some seismic waves travel over the Earthís surface. These are called surface waves.
- The fastest surface waves move the ground from side to side.†
- Other, slower waves travel like ocean waves over the surface of the Earth, moving the ground surface up and down. Most of the shaking that people feel during an earthquake is from these waves.
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