| A | B |
|---|
| earthquake | the shaking and trembling that results from the sudden movement of part of the Earth's crust |
| tsunami | a giant sea wave produced by an earthquake |
| focus | the underground point of origin of an earthquake, where the rocks break and move |
| epicenter | the point on the Earth's surface above the focus of an earthquake |
| seismic wave | an earthquake wave |
| primary (P) wave | a push-pull seismic wave, which can travel through solids, liquids, and gases; the fastest type of seismic wave |
| secondary (S) wave | a side-to-side seismic wave, which can travel through solids, but not through liquids and gases |
| surface (L) wave | a up-and-down seismic wave; the slowest moving |
| seismograph | an instrument that detects and measures seismic waves |
| seismologist | a scientist who studies earthquakes |
| seismogram | a record of seismic waves recorded by a seismograph |
| Richter scale | the scale used to measure the strength of earthquakes |
