Major Funding The Laura Moore Cunningham Foundation



Earthquakes: Glossary

A

aftershock
a smaller earthquake following the original

C

convergent boundary
boundary where two plates are moving toward each other
core
central part of the earth made of iron and nickel
crust
outer solid portion of the earth from 5 - 30 miles deep

D

divergent boundary
boundary between two plates that are moving apart

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
hypocenter
The point within the earth where an earthquake rupture begins, also known as the focus

I

intensity
strength

L

liquefaction
during an earthquake, solid surfaces can react like liquids

M

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

P

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

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

S waves
secondary waves of an earthquake which move up and down; these arrive slower than P-waves
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

T

tectonic plates
huge sections of the earth's surface that float on the mantle
transform plate boundary
boundary where two plates are moving past each other
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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