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Chapter 2
Question | Answer |
---|---|
stress | A force that acts on rock to change its shape or volume. |
shearing | Stress that pushes the mass of a rock in opposite directions. |
compression | Squeezes rock until it folds or breaks. |
tension | Pull on the crust, stretching rock so that it becomes thinner in the middle. |
deformation | Any change of shape or volume in earth's crust. |
fault | A break in earth's crust where slabs of crust slip past each other. |
strike-slip fault | Shearing can cause rock to break and slip apart or to change its shape. |
normal fault | Pulls on the crust, stretching rock so that it becomes thinner in the middle. |
hanging wall | Half of a fault that lies above is called the hanging wall. |
footwall | Half of that fault that lies below is called the foot wall. |
reverse fault | Squeezes rock until it folds or breaks. |
fault-block mountain | When normal faults uplift a block of rock. |
fold | Bends in a rock that forms when compression shortens and thickens a part of earth's crust. |
anticline | A fold in rock that bends upward into an arch. |
syncline | A fold in rock that bends downward into a bowl. |
plateau | A large area of flat land raised high up above sea level. |
focus | The pound beneath earth's surface where rock that is under stress breaks, triggering an earthquake. |
epicenter | The point above the surface directly above the focus. |
seismic waves | Vibrations traveling through earth carrying the energy released during an earthquake. |
P-Wave | Waves that compress and expand like an accordion. |
S-wave | Waves that vibrate side to side and up and down. |
surface wave | Move more slowly than P waves and S waves, but they produce the most severe ground moments. |
seismograph | Records seismic waves. |
magnitude | A measurement of earthquake strength. |
Mercalli Scale | Rate earthquakes according to their intensity. |
Richter Scale | A rating of the size of seismic waves. |
moment magnitude scale | Rate earthquakes of all sizes and near and far. |
aftershock | An earthquake that occurs after a larger earthquake in the same area. |
liquefaction | When an earthquake's violent shaking turns loose, soft soil into liquid mud. |
Tsunami | The water displaced from the quake forms large waves. |
base-isolated building | A building designed to reduce the amount of energy that reaches the building during an earthquake. |