Laying the Groundwork: Earth's Layers and Magnetism

These flashcards cover key vocabulary related to Earth's layers and magnetism, helping students prepare for their exam.

P waves

Seismic waves that can travel through both solids and liquids, and travel faster than S waves through rock.

S waves

Seismic waves that can only travel through solids and are slower than P waves.

Moho barrier

The boundary that separates the Earth's crust from the underlying mantle.

Seismic waves

Waves of energy induced by earthquakes that travel through the Earth.

Convection

The movement of fluid (such as rock in the mantle) caused by differences in temperature and density.

Upper mantle

The section of the mantle that lies between the crust and the lower mantle.

Lower mantle

The thicker, denser section of the mantle located beneath the upper mantle.

Oceanic crust

The part of Earth's crust that underlies the ocean, thinner and denser than continental crust.

Continental crust

The part of Earth's crust that forms the continents, thicker and older than oceanic crust.

Electromagnets

Magnets that are created by electric current and can be turned on and off.

Permanent magnet

A magnet that is always magnetized and retains its magnetic properties.

Dynamo theory

The theory that Earth's magnetic field is generated by the motion of molten iron in the outer core.

Fault

A break in the Earth's crust where blocks of land have moved.

Subduction zone

An area where one tectonic plate moves under another, sinking into the mantle.

Transform boundary

A tectonic plate boundary where two plates slide past each other horizontally.

Continental drift

The theory that continents have moved over geological time and were once joined together.

Seafloor spreading

The process by which new oceanic crust is formed at mid-ocean ridges and older crust is pushed away.

Thrust fault

A type of reverse fault with a shallow angle where the hanging wall moves up.