| A | B |
|---|
| EARTHQUAKE | The shaking that results from the movement of rock beneath Earth's surface. |
| STRESS | A force that acts on rock to change its shape or volume. |
| SHEARING | Stress that pushes a mass of rock in opposite directions. |
| TENSION | Stress that stretches rock so that it becomes thinner in the middle. |
| COMPRESSION | Stress that squeezes rock until it folds or breaks. |
| DEFORMATION | A change in the volume or shape of Earth's crust. |
| FAULT | A break or crack in Earth's lithosphere along which rock moves. |
| STRIKE-SLIP FAULT | A type of fault where rocks on either side move past each other sideways with little up-or-down movement. |
| 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 a 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 an earthquake's focus. |
| SEISMIC WAVES | A vibration that travels through Earth carrying energy released during an earthquake. |
| P WAVES | A type of seismic wave that compresses and expands the ground; parallel waves. |
| S WAVES | A type of seismic wave that moves the ground up and down or side-to-side; transverse waves. |
| SURFACE WAVES | A type of seismic wave that forms when P waves and S waves reach Earth's surface. |
| SEISMOGRAPH | A device that records ground movement caused by seismic waves as they move through Earth. |
| 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. |
