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20 terms

Earthquakes

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foreshock
a tremor that often precedes a major earthquake
aftershock
A tremor (or one of a series of tremors) occurring after the main shock of an earthquake
tremor
A fairly small earthquake.
surface waves
seismic waves that travel along the Earth's surface
seismology
The study of earthquakes
seismograph
an instrument that records vibrations in the ground and determines the location and strength of an earthquake
seismogram
A record of seismic waves usually a diagram on paper.
primary waves
Also called P-waves. Fastest moving seismic waves. P-waves push and pull objects in the same direction that the wave is traveling (think of the slinky).
secondary waves
Also called S-waves. Second-fastest moving seismic waves. S-waves shake objects at right angles to the directions that the wave is traveling (think of the rope).
intensity
A measure of the degree of shaking at a given location (based on the amount of damage).
magnitude
A more scientific measure based on calculations provided by the seismograms.
Richter scale
The first magnitude based scale, this scale is the most often used in the United States. It is based on the seismograph.
focus
Point at the depth where the rocks ruptured to produce earthquakes; place where quake waves originate.
epicenter
Point on Earth's surface directly above the focus
tsunami
A giant ocean wave that forms after a volcanic eruption, submarine earthquake, or landslide.
fault
A break in Earth's crust where slabs of rock slip past each other
active fault
A fault that's been active in the past 10,000 years.
plates
Large pieces of the Earth's crust that move due to convection currents.
transform fault
The most common fault that results in an Earthquake. The San Andres fault is the typical example in North America.
debris
Remains of something destroyed or broken down.