The Earth's magnetic field changes polarity during

Tectonic plates that move horizontally against each other.

Device used to map the ocean floor; detects small changes in magnetic fields

The long narrow depression that forms when continental crust begins to separate at a divergent boundary.

The huge pieces of crust and rigid upper mantle that fit together at their edges.

The vibrations of the ground during an earthquake.

Occurs when the nucleus of an atom is unstable and spontaneously emits energy in the form of radiation; causes uneven heating in Earth's lithosphere.

This is prodced by the electric currents generated by the flow of molten iron in the outer core.

Occurs when tectonic plates move away from each other.

This hypothesis explains the cycle of recycling rock on the sea floor; includes release of magma at mid-ocean ridges and subduction of older rock at deep-sea trenches.

Occurs when tectonic plates move toward each other.

The hypothesis that explains how dense, cold plates of the lithosphere sink into the mantle at deep-sea trenches.

A seismic wave that causes rock to move at right angles to the direction of the wave.

A numerical rating system used to express the magnitude of an earthquake.

The point on the surface located directly above the point of origin of an earthquake.

The hypothesis that states the weight of the elevated crust that forms at a divergent sea floor boundary acts as a driving force to move rock slabs at the opposing convergent boundary.

This seismic wave squeezes and pushes rock in the same direction the wave travels; fastest moving.

The name for the Earth's supercontinent that began to separate 200 Mya.

The process that occurs at a convergent boundary where the heavier plate slips beneath the less dense plate.

A fracture or a system of fractures in the Earth's crust that form when stress is applied to quickly or is too great.

The point of origin of an earthquake

Instrument used to record and measure the vibrations during an earthquake.

Measure of energy released during an earthquake

The record produced by a seismometer showing the arrival of seismic waves.

Uses sound to map the topography of the sea floor.

Convection currents ----.

Select all that apply.

Convergent boundaries lie opposite of ---

Choose all that apply.

The Ring of Fire is

The largest tectonic plate contains very little continental lithosphere. It is the

Tectonic plates move an average of ___ . Rates vary based on location.

Plates move on the semi-rigid mantle, not on water as suggested by the Continental Drift Theory.

Wegener's Continental Drift Theory provides extensive evidence explaining the existence of Pangaea.

The evidence includes:

Choose all that apply.

The current theory of Plate Tectonics disproves Wegener's Continental Drift Theory.

What can geologists determine by studying rock layers on the sea floor?

Which number on the diagram represents a tectonic plate?

Where does convection occur?

What type of plate boundary is pictured here?

Which epoch experienced the most polar reversals?

Name the current epoch.

What color represents the oldest rock on the sea floor?

What information can be obtained from an isochron map?

Choose 2.

Where does the transmission of the S-wave disappear?