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Devices that Monitor Faults

 * the geologists use machines to remember how the ground moves during an earthquake
 * to look closely at the differences in the ground, geologists put machines in the ground that tell if there is tension (stress) and if the ground starts to deform
 * sadly, earthquakes usually start without any notice
 * the only hint about an incoming earthquake is the little ascend or descend in the elevation or the slant of ground
 * the machines that geologists use to observe these motions are creep meters,laser ranging devices, tiltmeters, and satellites

Creep Meters

 * a creep meter uses a wire extended across a fault to measure the horizontal proposition of the earth on one side of a fault, the wire is tied to a pole on the other side of the fault, the wire is stuck onto a heavy item that can slide if the fault makes any movement.
 * geologists can see how much the fault has moved by taking a measurement of how much the heavy object has moved against the fault



Laser-Ranging Devices

 * a laser-ranging device uses a laser beam to find any small changes in the fault
 * this instrument measures the difference in the time that takes the laser beam to get to the reflector and return
 * this gadget can find any difference in the length to the reflector

Tiltmeters

 * it measures if there is any tilting on the ground
 * it uses to bulbs that are filled with liquid and is connected by a hollow stem
 * it can tell if the land rises or falls

Satellite Monitors

 * a satellite that bounces radio waves off the ground to detect if there's any change on the earth's surface
 * it can also take pictures of the ground surface to look if there are any changes on the earth's surface

Monitoring Risk in the United States

 * geologists can't predict when and where and earthquake will happen
 * geologists are able to tell where earthquakes will likely happen
 * by studying where active faults are
 * by studying where past earthquakes have occurred
 * the highest rick of earthquakes are
 * along the Pacific coast of the states in California, Washington, and Alaska
 * the reason why the risk is so high here is because this is where the Pacific and North America plates meet
 * some very dangerous earthquakes occur on the east of the Rocky Mountains

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