| A | B |
|---|
| earthquake | Energy given off through movement along a fault line. |
| epicenter | On the surface above the focus where an earthquake occurs. |
| secondary wave | A side-to-side seismic wave that can only travel through solids. |
| seismograph | An instrucment used to detect seismic waves. |
| seismologist | A scientist who studies earthquakes. |
| Mercalli scale | Method of rating an earthquake, based on visual observations. |
| fault | A break along which rocks move. |
| vent | The opening of a volcano. |
| volcanic ash | Rock particles smaller than cinders but larger than dust. |
| volcanic dust | Fine rock particles that can circulate in the atmosphere for years. |
| shield volcano | A volcano composed of quiet lava flows. |
| pyroclastic flow | Explosive eruptions of dust, ash, cinders, bombs, gas, and heat from a volcano. |
| Mid-Atlantic Ridge | Earthquake and volcano zone located in the center ofthe Atlantic Ocean. |
| magma | Molten rock beneath the Earth's surface. |
| cinder cone | A volcano consisting mostly of cinder from violent, explosive eruptions. |
| cinder | Small volcanic bombs. |
| composite volcano | A volcano built from alternating layers of rock particles and lava. |
| crater | A funnel-shaped pit at the top of a volcanic cone. |
| caldera | A pit at the top of a volcanic cone that is wider than it is deep. |
| focus | The underground point of origin of an earthquake. |
| lava | Molten rock at the Earth's surface. |
| primary wave | A push-pull seismic wave that can travel through solids, liquids, and gases. |
| Richter scale | Method of rating an earthquake based on seismograph measurements. |
| Ring of Fire | The earthquake and volcano zone surrounding the Pacific Ocean. |
| seismic wave | A general term used to describe all earthquake waves. |
| seismogram | A record of seismic waves recorded from a seismograph. |
| stress | Forces from the interior of the Earth that deform the Earth's surface. |
| volcano | A location on the Earth's surface where magma and other material reach the Earth's surface. |
| volcanic bomb | The largest rock particles blown into the air from an eruption. |
| tsunami | A giant sea wave. |
| surface wave | An up-and-down seismic wave that originates and causes great destruction on the Earth's surface. |
