| Term | Definition |
|---|
| stress | a force that acts on rock to change its shape or volume |
| tension | the stress force that pulls on the crust, stretching it so that it becomes thinner in the middle |
| compression | the stress force that squeezes rock until it folds or breaks |
| shearing | the stress force that pushes a mass of rock in two opposite directions |
| hanging wall | the block of rock that lies above a normal fault |
| footwall | the block of rock that lies below a normal fault |
| strike-slip fault | the rocks on either side of the fault slip past each other sideways, with little up or down motion |
| anticline | a fold in rock that bends upward into an arch |
| syncline | a fold in rock that bends downward |
| earthquake | the shaking and trembling that results from the movement of rock beneath Earth's surface |
| focus | the area beneath Earth's surface where rock that is under stress breaks, triggering an earthquake |
| epicenter | the point on the surface directly above the focus |
| P(rimary) wave | seismic waves that compress and expand the ground like an accordion |
| S(econdary) wave | seismic waves that vibrate from side to side as well as up and down |
| surface wave | seismic waves that move slower than P and S waves, but can produce more severe ground movements |
| Mercalli scale | a scale developed to rate earthquakes according to the level of damage at a given place |
| magnitude | a number that geologists assign to an earthquake based on the earthquake's size |
| Richter scale | a rating of an earthquake's magnitude based on the size of the earthquake's seismic waves |
| seismograph | an instrument that records and measures seismic waves |
| moment magnitude scale | a rating system that estimates the total energy relased by an earthquake |
| seismogram | the record of an earthquake's seismic waves produced by a seismograph |
| liquefaction | when loose, soft soil turns into liquid mud as a result of an earthquake's violent shaking |
| aftershock | the earthquake that occurs after a larger earthquake in the same area |
| tsunami | when water that is displaced by an underwater earthquake spreads out from the epicenter and speeds across the ocean |
| base-isolated building | a building designed to reduce the amount of energy that reaches the building during an earthquake |
Combine with other sets
Share on Facebook
Share on MySpace
!