SBSK+2.2

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Vocabulary

 * focus**-rock under the surface breaks,creating an earthquake
 * epicenter**-point directly above the surface
 * seismic waves**-carries energy released in an earthquake
 * P waves**-waves that squeeze and stretch the Earth
 * S waves**-waves that move from side-to-side as well as up-and-down
 * Surface waves**-waves that move like ocean waves
 * seismograph**-records ground movements caused by seismic waves
 * magnitude**-measurement of Earthquake strength
 * Mercalli scale**-rates earthquake on strength
 * Richter scale**-rating of how big a seismic wave is
 * moment magnetude scale-**rates total energy of an earthquake

seismic waves

 * energy is greatest at the epicenter
 * primary waves(P waves)
 * squeezes and stretches the ground
 * causes buildings to do the same thing as the ground
 * Secondary Waves (S waves)
 * comes after P waves
 * moves from side-to-side as well as up-to-down
 * shakes buildings viciously
 * Surface Waves
 * makes more severe earthquakes
 * rolls like ocean waves
 * P waves come first, then S waves, then Surface Waves

Detecting Seismic Waves

 * seismograph records ground movements

Measuring Earthquakes
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 * Magnitude is the measurement of Earthquakes
 * The Mercalli Scale
 * developed in early 20th century
 * rates Earthquakes on Strength
 * The Richter Scale
 * developed in 1930s [[image:SBSK_2.2.jpg]]
 * rates how big a seismic wave is
 * The Moment Magnitude Scale
 * rates the energy released during an Earthquake

Locating the Epicenter

 * Geologists use seismic waves to locate the Earthquake's epicenter
 * the farther away the Earthquake,the more time of the arrival of the P and S waves

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