You might find yourself on the wrong side of the news if you aren't familiar with earthquake terminology. These terms were mostly Greek to me when I first moved to California, but everyone should probably be familiar with them.
A second (or third or fourth) quake of usually less intensity that comes after the mainshock.
Earthquake
A sudden movement of one tectonic plate over another, deep in the earth's crust, causing vibrations all the way up to the surface.
Earthquake Risk
The likely damage to a structure and threat to human beings if an earthquake occurs in a certain place.
Epicenter
The exact spot on the surface on the earth above where the earthquake begins. Once the fault beings to slip, it can expand as much as hundreds of miles before it stops.
Fault
The actual fracture between tectonic plates.
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Hypocenter
The point deep within the earth, and directly under the epicenter, where an earthquake begins.
Landslide
The sudden movement of rocks, mud or soil down a slope, often triggered by an earthquake.
Magnitude
The measure of energy released by an earthquake, determined by the amplitude of seismic waves.
Mainshock
The largest quake in a sequence. Mainshocks sometimes follow smaller foreshocks and are followed by aftershocks.
Richter Scale
Named for Charles Richter of Cal Tech, who sought to create a scale of earthquake severity. Each incremental whole number on the Richter Scale represents ten times the amplitude and 31 times the energy of the previous number.
Seismic Waves
Vibrations that travel from the hypocenter at several miles per second. The energy from seismic waves causes far more damage than the actual slippage of the fault beneath the surface.Vibrations that travel outward from the earthquake fault at speeds of several miles per second.
Seismograph
This instrument is used to record and measure earthquakes by detecting, amplifying and recording ground vibrations.
