JBTC2.2

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Notes 2.2

 * focus** - the point where rocks under pressure breaks, making an earthquake
 * epicenter** - the place right above the focus
 * seismic waves** - vibration that travel through the Earth, with energy that is directly above the focus
 * primary waves** - earthquake waves that expand and close together like a spring toy
 * secondary waves** - earthquake waves that goes up and down
 * surface waves** - surface travels more slowly, but the damage is greater
 * seismograph** - records how hard the earthquake shakes
 * magnitude** - a measurement for earthquakes
 * Mercalli scale** - a device to measure earthquake with it's intention
 * Richter scale** - a measurement of size seismic waves
 * Moment Magnitude scale** - used to measure earthquakes no matter how hard it is

Seismic Waves

 * moves like ripples in a pond
 * travels out in all direction
 * travels from the focus
 * S waves
 * more severe
 * P waves
 * vibrates back and forth
 * Surface waves
 * move more slowly than P waves or S waves

Detecting Seismic Waves

 * seismograph
 * Seismic waves

Measuring Earthquakes

 * Mercalli Scale
 * Rithcher Scale
 * Moment Magnitude Scale

Locating The Epicenter

 * Arrival times af Pwaves and S waves
 * P waves arrive before S waves

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