| A | B |
|---|
| Compression | Stress that squeezes rock until it folds or breaks |
| Shearing | Stress that pushes a mass of rock in opposite directions |
| Tension | Stress that stretches rock so that it becomes thinner in the middle |
| Normal fault | A type of fault where the hanging wall slides downwards; caused by tension in the crust. |
| Reverse fault | A type of fault where the hanging wall slides upwards. |
| Strike slip fault | A type of fault where rocks on either side move past each other sideways with a little up-or-down motion. |
| Stress | A force that acts on rock to change its shape or volume. |
| Anticline | An upward fold in the Earth’s crust |
| Syncline | A downward fold in the Earth’s crus |
| Earthquake | The shaking that results from movement of rock beneath Earth’s surface. |
| Epicenter | The point on Earth’s surface directly above an earthquake’s focus. |
| Focus | The point beneath Earth’s surface where rock breaks under stress and causes an earthquake. |
| Primary wave (P-wave) | A type of seismic wave that compresses and expands the ground. |
| Secondary wave (S-wave) | A type of seismic wave that moves the ground up and down or side to side. |
| Surface wave | A type of seismic wave that forms when P waves and S waves reach Earth’s surface. |
| Tsunami | A large wave produced as the result of an impact to ocean water. |
| Seismograph | A device that records ground movements caused by seismic waves as they move through Earth. |
