| A | B |
|---|
| earthquakes | shaking and trembing of the earth's crust |
| tsunami | giant sea waves |
| focus | underground point of orgin of an earthquake |
| epicenter | point on the Earth's surface directly above the focus |
| seismic | an earthquake wave |
| primary wave, P wave | fast moving, push-pull earthquake waves that travel through solids, liquids and gases |
| secondary wave, S wave | side-to-side earthquake waves that travel through solids |
| surface wave, L wave | earthquake waves with slow moving, circular motion, that travel only on the Earth's surface |
| seismograph | detects and measures seismic waves |
| seismologist | scientist who studies earthquakes |
| seismogram | a record of seismic waves recorded by a seismograph |
| Richter scale | measures the strength of a volcano |
| magma | molten rock beneath the Earth's surface |
| lava | molten rock at the Earth's surface |
| volcano | place through which molten rock reach the surface |
| vent | an opening through which lava excapes |
| volcanic dust | smallest particles from volcanic eruption |
| shield volcano | volcano made from quiet lava flows |
| cinder cone | a volcano made mostly of cinders |
| cinder | small rough volcanic bomb of a few centimeters |
| composite volcano | a volcano made of alternating layers of rock particles and larva |
| crater | funnel-shaped pit at the top of a volcano |
| caldera | a steep-sided pit at the top of a volcano |
| Ring of Fire | the earthquake and volcano zone that encircles the Pacific Ocean |
