Richter scaleused to measure the

amount of energy releasedby an earthquake

convergent boundarya place where the Earth's

tectonic plates pushagainst each other

core the center of the Earth made mostly of iron andnickel; the outer core is

liquid and the inner core is solid

crust the upper layer of theEarth, on which we live,broken into pieces calledtectonic plates that float

on the mantle

deposition the process by which sediment, which has been

transportedby erosion, is dropped some-where on the Earth's surface

divergent boundarya place where the Earth's

tectonic plates are movingaway from each other

earthquakes

the violent shaking of theEarth that occurs when a

tectonic plate snaps

epicenterthe location on the surfaceof the Earth directly above where an earthquake starts

erosionthe movement of rocks and

soil from one place toanother by the forces of

gravity, water, ice, or wind

fault a break in the Earth's crustthat results in the groundmoving along the line of

the break

fossil the preserved remains ofan animal, plant, or other

organism from some geologic

or prehistoric time

geologist a scientist who studiesthe Earth's physicalstructure and all the

events that helped shape it

igneous rockrocks that form when hotmagma or lava cool and

harden

lava magma that has eruptedfrom a volcano or a fissure

in the Earth's crust

metamorphic rock created when rock deep inthe Earth's crust is exposed

to so much heat and pressure that it changes into

something new

minerals solid, pure substances thatcan be found in the Earth's crust; every rock is made

of a combination of different minerals

rock cycle

the continuous process bywhich new rocks is made and

old rock is destroyed or changed from one form to

another; the three forms of rock are igneous, metamorphic, and

sedimentary

sediment small particles of weatherrock carried away by wind and water; can also come

from decomposed plants and animals that have drifted down to the bottom of a

body of water

sedimentary rock

formed by layers of rockthat have been eroded

and then pressed togetherand hardened

tectonic plates parts of the Earth's crust thatrest on the very dense hot rockof the mantle and as they float

around, the plates can pull apart, slide next to each other,

ormove toward each other

transform boundary a place where theEarth's plates slide

alongside each other

tsunami a huge surge of water caused by earthquakes or volcanic

eruptions under the sea; as the tsunami approaches a coastline, the large mass of water rushing

onshoreis so powerful it destroys

everything in its path

weathering the wearing down andbreaking up of hard rock

by natural forces like wind,ice, plants, and

burrowing animals

-divergent boundary-convergent boundary-transform boundary