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Inside earth # 2
Term | Definition |
---|---|
stress | A force acting on rock to change its shape or volume. |
shearing | Stress that pushes masses of rock in opposite directions |
compression | Stress that squeezes rock until it folds or breaks |
tension | Stress that stretches rock so that it becomes thinner in the middle. |
deformation | A change in the volume or shape of Earth’s crust. |
fault | a break in Earth's crust where slabs of rock slip past each other. |
strike-slip fault | A fault where rocks on either side move past each other sideways with little up-or-down motion. |
normal fault | A fault where the hanging wall slides downward; caused by tension in the crust. |
hanging wall | The block of rock that lies above a fault line. |
foot wall | The block of rock that lies below the fault line. |
reverse fault | A type of fault where the hanging wall slides upward. |
fault-block mountain | A mountain that forms where a normal fault uplifts a block of rock. |
fold | A bend in rock that forms where part of Earth’s crust is compressed. |
anticline | An upward fold in rock formed by compression of Earth’s crust. |
syncline | A downward fold in rock formed by compression in Earth’s crust. |
plateau | A large area of flat land elevated high above sea level. |
focus | The point beneath Earth’s surface where rock breaks under stress and causes an earthquake. |
epicenter | Point on the Earth’s surface directly above the earthquake’s focus |
seismic waves | vibrations that travel through the earth carrying the energy released during an earthquake |
P-Wave | A type of seismic wave that compresses and expands the ground. It is the fastest seismic wave. |
S-wave | A type of seismic wave that moves the ground up and down or side to side. S-waves are slower than P-waves and cannot travel through a liquid. |
surface wave | Type of seismic wave that forms when P and S waves reach Earth’s surface. Causes the most damage. |
seismograph | A machine that records ground movements caused by seismic waves as they move through the Earth. |
magnitude | Measurement of earthquake strength based on seismic waves and movement along faults. |
Mercalli Scale | A scale that rates earthquakes according to how much damage they cause at a particular place. |
Richter Scale | *Scale for measuring earthquakes, *Each step in the scale is 10 times more powerful than the step below. |
moment magnitude scale | A rating system that estimates the total energy released by an earthquake. Used today. |
aftershock | An earthquake that occurs as a result of a larger previous earthquake. |
liquefaction | a temporary state in which loose soil and rock materials take on the property of liquid, often as a result of severe ground-shaking. (Basically makes quicksand) |
Tsunami | "Harbor Wave" - seismic sea wave that begins over an earthquake focus and can be highly destructive when it crashes on shore |
base-isolated building | A type of seismic -safe building designed to reduce the amount of energy that reaches building during earthquake. Sits on rubber pads or springs - like car. |