Forces in Earth's Crust
A force that acts on rock to change its shape or volume.
Stress
A type of fault where the hanging wall slides upward; caused by compression in the crust.
reverse fault
The shaking that results from the movement of rock beneath Earth’s surface.
earthquake
A type of seismic wave that forms when P waves and S waves reach Earth’s surface.
surface wave
A scale that rates earthquakes by estimating the total energy released by an earthquake.
moment magnitude scale
Stress that stretches rock so that it becomes thinner in the middle.
tension
A type of fault in which rocks on either side move past each other sideways with little up or down motion.
strike-slip fault
The point beneath Earth’s surface where rock first breaks under stress and causes an earthquake.
focus
A device that records ground movements caused by seismic waves as they move through Earth.
seismograph
The record of an earthquake’s seismic waves produced by a seismograph.
Seismogram
Stress that squeezes rock until it folds or breaks. 2. The part of a longitudinal wave where the particles of the medium are close together.
compression
A large landform that has high elevation and a more or less level surface.
plateau
The point on Earth’s surface directly above an earthquake’s focus.
epicenter
A scale that rates the amount of shaking from an earthquake.
Modified Mercalli scale
Stress that pushes masses of rock in opposite directions, in a sideways movement.
shearing
A type of seismic wave that compresses and expands the ground.
P wave
The measurement of an earthquake’s strength based on seismic waves and movement along faults.
magnitude
A type of fault where the hanging wall slides downward; caused by tension in the crust.
normal fault
A type of seismic wave in which the shaking is perpendicular to the direction of the wave.
S wave
A scale that rates an earthquake’s magnitude based on the size of its seismic waves.
Richter scale