APES - Plate Tectonics

Theory of Plate tectonic

The theory that pieces of Earth's outer layer are in constant motion

Alfred Wegener (1880-1930)

Continental drift (1915): Hypothesized that the continents were slowly drifting around the Earth. His hypothesis was not accepted until the 1950s, when numerous discoveries provided conclusive evidence (plate tectonics).

tectonic plates

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

convection current

a current caused by the rising of heated fluid and sinking of cooled fluid

Convergent boundary

A plate boundary where two plates move toward each other.

Convergent Boundary (Continental/Continental)

when two continental plates collide creating mountains

Subduction zone(Continental/Oceanic)

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

Divergent boundary

A plate boundary where two plates move away from each other.

Plate boundaries

the edges of tectonic plates.

Ridge

A long, narrow chain of hills or mountains

Seafloor spreading

The formation of new ocean crust as a result of magma pushing upward and outward from Earth's mantle to the surface.

Pangea

A supercontinent containing all of Earth's land that existed about 225 million years ago.

Transform boundary

The boundary between tectonic plates that are sliding past each other horizontally

Seismograph

a device that measures the strength of an earthquake

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.

epicenter

Point on Earth's surface directly above an earthquake's focus

Magnitude

Measure of the energy released during an earthquake

Fault

A break in the earth's crust

Richter scale

a logarithmic scale of 1 to 10 used to express the energy released by an earthquake