earthquake
the vibration of Earth produced by the rapid release of energy within the lithosphere
fault
fractures in Earth where movement has occurred
focus
the point within Earth where an earthquake starts
seismic waves
vibrations that travel through Earth carrying the energy released during an earthquake
epicenter
the location on the surface directly above the focus of an earthquake
uplifted crust
crust that has been moved up vertically by an earthquake
fault scarp
sharp-edged ridge formed by vertical crust movement
offset crust
displaced; crust that has been moved horizontally by an earthquake
elastic rebound hypothesis
most earthquakes are produced by the rapid release of energy stored in rock that has been subjected to great forces and when the the strength of the rock has been exceeded, it suddenly breaks, releasing some of its stored energy as seismic waves
elastic rebound
the tendency for deformed rock along a fault to spring back after an earthquake
aftershock
an earthquake that occurs hours or even weeks after a major earthquake
foreshock
small earthquake that occurs sometime before a major earthquake
body waves
seismic waves that travel through Earth's interior
P waves
compressional waves; seismic waves that push and pull particles in the direction the waves travel
S waves
transverse waves; shake particles at right angles to the wave's direction of travel
surface waves
seismic waves that travel along the surface of Earth
seismograph
an instrument that records seismic waves
seismogram
the record made by a seismograph
intensity
a measure of the amount of earthquake shaking at a given location based on the amount of damage
magnitude
a measure of the size of seismic waves or the amount of energy released at the source of the earthquake
moment magnitude
a more precise measure of earthquake magnitude than the Richter scale, which is derived from the amount of displacement that occurs along a fault zone and estimates the energy released by an earthquake
Modified Mercalli scale
scale the rates earthquakes' intensity in terms of the earthquakes' effects at different locations