| A | B |
|---|
| earthquake | shaking that happens when the Earth's crust moves suddenly |
| tsunami | giant sea wave produced by earthquakes |
| focus | underground point where the earthquake starts |
| epicenter | place on the Earth's surface directly above the focus of an earthquake |
| seismic wave | shock wave made by earthquakes that travel through the Earth |
| Primary wave (p) | push pull seimic wave, travels through solids, liquids, gas, fastest type of wave |
| secondary wave (S) | earthquake wave moves side to side, slower than p waves only moves through solids |
| surface waves (L) | earthquake waves that move up and down, slowest seismic waves |
| seismologist | scientist who studies earthquakes |
| seismogram | record of seismic waves recorded on a seismograph |
| Richter Scale | scale used to measure the strength of earthquakes |
| magma | molten rock beneath the Earth's surface |
| lava | molten rock on the Earth's surface |
| volcano | place on the Earth's surface where molten rock and other materials reach the surface |
| vent | opening through which lava erupts |
| volcanic dust | smallest particles blown out by a volcanic eruption |
| volcanic ash | rock from volcanic eruptions more than .25 mm and less than 5mm |
| volcanic bomb | particles from volcanic eruption larger than 5mm |
| cinder | small, rough volcanic bomb no more than several cm across |
| cinder cone | volcano made of cinders and rock particles that have been blown into the air |
| shield volcano | gently sloping volcano formed when runny lava flows over a large area |
| composite volcano | volcano built of alternating layers of rock particles and lava |
| crater | funnel-shaped pit or depression at the top of a volcanic cone |
| caldera | large crater made when the sides of a volcanic cone collapse |
| Ring of Fire | earthquake and volcano zone that circles the Pacific Ocean |
