| A | B |
|---|
| earthquake | the shaking that results from the movement of rock beneath Earth's surface |
| stress | a force that acts on a rock to change its shape or volume |
| shearing | stess that pushes a mass of rock in opposite direction |
| tension | stress that stretches rock so that it becomes thinner in the middle |
| compression | stress that squeezes rock unitl it folds and breaks |
| deformation | a change in the volume or shape of Earth's crust |
| fault | a break or crack in Earth lithosphere along which the rocks move |
| strike-slip fault | a type of fault where rocks on either side move past each other sideways with little up-or-down motion |
| normal fault | a type of fault where the hanging wall slides downward; caused by tension in the crust |
| hanging wall | the block of rock that forms the upper half of a fault |
| footwall | the block of rock that forms the lower half of the fault |
| reverse fault | a type of fault where the hanging wall slides upward; caused by compression in the crust |
| fault-block mountain | a mountain that forms where a normal fault uplifts a block of rock |
| folds | 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 landform that has a more or less level surface and is elevated high above sea level |
| focus | the point beneath Earth's surface where rock breaks under stress and causes an earthquake |
| epicenter | the point on Earth's surface directly above the earthquake's focus |
| seismic waves | a vibration that travels through Earth carrying the energy released during an earthquake |
| P waves | the type of waves that compress and expand the ground |
| S Waves | the type of waves that move the ground up and down or side to side |
| surface waves | the type of seismic wave that forms when P waves and S waves reach Earth's surface |
| seismograph | a device that records ground movements caused by seismic waves as they move through Earth |
| magnitude | the measurement of an earthquake's strength based on seismic waves and movement along faults |
| Mercalli scale | a scale that rates earthquakes according to their intensity and how much damage they cause |
| Richter scale | a scale that rates seismic waves as measured by a mechanical seismograph |
| moment magnitude scale | a scale that rates earthquakes by estimating the total energy released by an earthquake |
| liquefaction | the process by which an earthquake's violent movement suddenly turns loose soil into liquid mud |
| aftershock | an earthquake that occurs after a larger earthquake in the same area |
| tsunamis | a giant wave caused by an earthquake on the ocean floor |
| base-isolated building | a building mounted on bearings designed to absorb the energy of an earthquake |
