Layers of the Earth and Earth Processes

iron and nickel

What is the core made of?

mountain range

a series of connected mountains

earthquake

a sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action.

destructive

causing great and irreparable harm or damage.

Compositional layers of Earth

crust, mantle, core

trench

extremely deep areas in the ocean that are created by a subducting plate

constructive

having a positive effect; helpful

subduction zone

in tectonic plates, the site at which an oceanic plate is sliding under a continental plate.

Inner Core

A dense sphere of solid iron and nickel at the center of Earth

Outer Core

A layer of molten iron and nickel that surrounds the inner core of Earth

Density

A measure of how much mass there is in a volume of a substance.

transform boundary

A plate boundary where two plates move past each other in opposite directions

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

convergent boundary

A tectonic plate boundary where two plates collide, come together, or crash into each other.

Convection Currents

Circular currents in the upper mantle (mainly the Asthenosphere) caused by the magma being heated by the core off the Earth.

tectonic plates

Sections of the Earth's crust that move due to convection currents.

divergent boundary

The boundary between two tectonic plates that are moving away from each other

continental drift

The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

Mesosphere

The lowest part of the Mantle where the rock hardens into a solid.

Continental Crust

The portion of the earth's crust that primarily contains granite, is less dense than oceanic crust, and is 20-50 km thick

seafloor spreading

The process that creates new sea floor as plates move away from each other at the mid-ocean ridges

Asthenosphere

The solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it

Physical Layers of the Earth

lithosphere, asthenosphere, mesosphere, outer core, inner core

Oceanic Crust

the portion of Earth's crust that is usually below the oceans and not associated with continental areas, thinner and higher in density than continental crust and made up of basalt instead of granite.

Plate Tectonic Theory

the theory that the lithosphere is broken up into large plates that move and then rejoin; considered the unifying theory of geology

seismic waves

vibrations that travel through Earth carrying the energy released during an earthquake; scientists use these to study the layers of the Earth