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Earthquakes: Glossary

A

aftershock
a smaller earthquake following the original

C

core
central part of the earth made of iron and nickel
crust
outer solid portion of the earth from 5 - 30 miles deep

E

earthquake
sudden, rapid shaking of the earth's crust caused by moving tectonic plates
epicenter
a location on the earth's surface directly above the earthquake's focus

F

fault
the place where tectonic plates meet or come together
foci
plural form of the word focus
focus
a location inside the earth where the earthquake takes place

G

geologist
scientist who studies the earth

H

hazard
danger

I

intensity
strength

L

liquefaction
during an earthquake, solid surfaces can react like liquids

M

magnitude
the amount of energy released from an earthquake
mantle
the melted layer of the earth just below the crust
Mercalli Intensity Scale
a method of measuring earthquakes based on visual observation - uses a scale of 1-12

P

plate margin
the area where two tectonic plates meet
P waves
primary or first waves of an earthquake that move longitudinally

R

Richter Scale
a method of measuring earthquakes based on seismographic readings
Ring of Fire
an active zone around the pacific ocean where plates of oceanic crust slip under the continental crusts - 4 out of 5 earthquakes take place along the pacific ring of fire - a huge number of volcanoes lie in the area too

S

seismogram
the paper output from a seismograph machine
seismograph
a sensitive piece of equipment used to measure and determine intensity of earthquakes
seismologist
a scientist - sometimes a geologist - whose study pertains to earthquakes
seismology
the science of using readings from a seismograph to determine intensity of earthquakes
shockwave
waves of energy that travel through the Earth's layers as a result of an earthquake; also known as seismic waves
S waves
secondary waves of an earthquake which move up and down; these arrive slower than P-waves

T

tectonic plates
huge sections of the earth's surface that float on the mantle
tremors
the shaking or trembling of the earth is sometimes called a tremor; another word for earthquake
tsunami
a huge wave caused by sudden movement of the earth's surface - usually related to an earthquake or volcano

V

volcano
an opening in the earth's crust through which molten rock and gases are released
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