| Term | Definition |
|---|
| stress | a force that acts on an area of rock to change its shape or volume |
| tension | pulling on the crust stretching rock so that it becomes thinner in the middle |
| compression | squeezing rock until it folds or breaks |
| shearing | pushing a mass of rock in opposite directions to cause rock to break and slip apart, or to change its shape |
| normal fault | tension in Earth's crust that pulls rock apart so one block of rock lies above the other block of rock |
| hanging wall | the block of rock that lies above |
| footwall | the block of rock that lies beneath |
| reverse fault | the same structure as a normal fault, but the blocks move in opposite directions |
| strike-slip fault | the rocks on either side of a fault slip past each other sideways with little up or down motion |
| plateau | a large area of flat land elevated high above sea level |
| earthquake | the shaking that results from the sudden movement of rock along a fault |
| focus | the area beneath Earth's surface where rock that is under stress breaks, triggering an earthquake |
| epicenter | the point on the surface directly above the focus |
| p waves | seismic waves that compress and expand the ground like an accordion |
| s waves | seismic waves that vibrate from side to side as well as up and down |
| surface wave | a type of seismic wave that forms when p and s waves reach the Earth's surface |
| mercalli scale | a scale that rates earthquakes according to their intensity and how much damage they cause at a particular place |
| magnitude | a number that geologists assign to earthquakes based on the quake's size |
| richter scale | a scale that rates an earthquake's magnitude based on the size of its seismic waves |
| seismograph | an instrument that records and measures seismic waves |
| moment magnitude scale | a rating system that estimates the total energy released by an earthquake |
| seismogram | the record of an earthquake's seismic waves produced by a seismograph |
| friction | the force that opposes the motion of one surface as it moves across another surface |
| liquefaction | the process by which an earthquake's violent movement suddenly turns loose soil into liquid mud |
| aftershock | an earthquake after a larger earthquake in the same area |
| tsunami | a giant wave usually caused by an earthquake beneath the ocean floor |
| base-isolated building | a building mounted on bearings that absorb an earthquake's energy |
Combine with other sets
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