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

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

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