| A | B |
|---|
| seismology | the study of earthquakes |
| fault | a break in the Earth's crust along which block of the crust slide relative to one another |
| deformation | the change in the shape of rock in response to stress |
| elastic rebound | the sudden return of elastically deformed rock to its original shape |
| reverse faults | causes strong deep earthquakes |
| normal faults | causes weak. shallow earthquakes |
| strike-slip fault | causes moderate, shallow earthquakes |
| seismic waves | waves of energy that travel through the Earth |
| body waves | seismic waves that travel through the Earth's interior |
| P waves | travel through solids, liquids, and gases |
| S waves | shear back and forth, secondary waves |
| surface waves | waves that move the ground up and down |
| siesmographs | instrument that detects earthquakes |
| seismogram | a tracing of earthquake motion |
| epicenter | the point on the Earth's center directly above the earthquake's starting point |
| focus | the point inside the Earth where the earthquake begins |
| volcano | a mountain that forms when molten rock is forced to the Earth's surface |
| lava | magma that flows onto the Earth's surface |
| explosive eruption | clouds of hot debris and gases shoot out from the volcano |
| What causes a volcano to be explosive | high water content, silica rich magma |
| vents | holes in the Earth's crust |
| magma chamber | area in the earth where the magma is stored |
| pyroclastic material | rock fragments created by explosive volcanic eruptions |
| shield volcano | nonexplosive eruptions |
| cindercone volcano | made of pyroclastic material, erodes quickly |
| composite volcano | the most common type of volcanoes |
| crater | funnel-shaped pit at the top of the volcano |
| calderas | forms when a magma chamber empties and its roof collapses |
| rift | a deep crack |
| hot spots | places on the Earth's surface direct above mantle plumes |
| tiltmeter | measures the slope of volcanoes |
