| A | B |
|---|
| seismology | the study of earthquakes |
| fault | a break in the Earth's crust along which blocks of the crust slide relative to one another due to tectonic forces |
| deformation | the change in the shape of rock in response to stress |
| elastic rebound | the sudden return of elastically deformed rock to its undeformed shape |
| seismic waves | waves of energy that travel through the earth |
| P waves | fastest type of seismic wave (primary waves) |
| S waves | the second-fastest type of seismic wave (secondary waves) |
| seismograph | an instrument located at or near the surface of the Earth that records seismic waves |
| seismogram | a tracing of earthquake motion created by a seismograph |
| epicenter | the point on the Earth's surface directly above an earthquake's starting point |
| focus | the point inside the Earth where an earthquake begins |
| gap hypothesis | states that sections of active faults that have had relatively few earthquakes are likely to be the sites of strong earthquakes in the future |
| seismic gap | an area along a fault where relatively few earthquakes have occurred |
| magnitude | A measure of the strength of an earthquake |
| intensity | a measure of the degree to which an earthquake is felt by people and the amount of damage caused |
| surface waves | seismic waves that travel along the Earth's surface |
| body waves | seismic waves that travel through the Earth's interior |
