Earth Science - Layers of the Earth, Plate Tectonics and Earthquakes

Flashcards about the layers of the Earth, plate tectonics, earthquakes, and continental drift theory.

What is the Earth's crust?

Uppermost layer made of solid rocks with a density of 2.8 g/cm3 and thickness of 5 to 50 km.

What is the mantle?

The biggest layer of the Earth.

What is the core?

The hottest layer of the Earth, composed of a solid inner part and a liquid outer part made of Iron and Nickel.

What is the lithosphere?

Composed of the crust and the upper part of the mantle.

What is continental crust?

Less dense type of crust.

What is oceanic crust?

More dense type of crust.

What are tectonics?

Plates that move very slowly and constantly.

What are plates?

A rigid section of the lithosphere that moves as a unit.

What is plate tectonics?

A theory about the moving lithospheric plates.

What is an earthquake?

The shaking or trembling caused by the sudden release of energy, usually associated with faulting or breaking of rocks.

What are faults?

Cracks between blocks of rock that allow them to shift in relation to one another.

What is stress?

A force that squeezes, stretches, or pushes rocks in different directions.

What are faults?

A break in the Earth's crust along which significant movement has taken place.

What is the focus of an earthquake?

The place where the first break happens, where the fault starts to slip, where first movement takes place.

What is the epicenter of an earthquake?

The spot directly above the focus on the surface of the Earth.

What are seismic waves?

The energy released during an earthquake that is carried by vibrations.

What is a seismograph?

A device that can detect and record seismic waves.

What is a seismogram?

The record of an earthquake on a seismograph.

What is intensity of an Earthquake?

Effects on people or surroundings, gives an idea of how strong or weak the shaking is, scale using Roman Numerals (I-X).

What is magnitude of an Earthquake?

Refers to the energy released of an earthquake, scale using Hindu-Arabic Numerals 1-9.

What is a tectonic earthquake?

Occurs when plates move and the earth's crust breaks due to geological forces.

What is a volcanic earthquake?

Results from tectonic forces which occur in conjunction with volcanic activity.

What is an explosive earthquake?

The result of the detonation of a nuclear or chemical device.

What is a collapse earthquake?

Small earthquakes in underground caverns and mines caused by seismic waves from the explosion of rock on the surface.

What are plate boundaries?

The lines at the edges of the different pieces of the lithosphere.

What are Divergent boundaries?

Plates that separate and move apart in opposite directions forming new lithosphere.

What are Convergent boundaries?

Are formed when two plates move toward each other.

What are transform-fault boundaries?

Are plates sliding past or slipping past each other.

How is the rock pulled at Divergent Boundaries?

Rock gets THIN in the middle as it is pulled apart, this STRESS is called Tension.

What is compression?

The stress in boundaries between two plates that are colliding.

What is Oceanic-Continental Convergence?

Ocean plate colliding with a less dense continental plate.

What is a subduction zone?

The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.

What is Oceanic-Oceanic Convergence?

Ocean plate colliding with another ocean plate.

What is Continental-Continental Convergence?

A continental plate colliding with another continental plate.

What are collision zones?

A place where folded and thrust faulted mountains form.

What is shearing during a transform fault boundary?

Rock is pushed in two opposite directions, this stress is called shearing.

What is subduction process?

The process by which a plate dives under a less dense plate.

What is mantle plume?

the column of rising magma

What is a trench?

A depression on the ocean floor it is a result of subduction process.

What is Tsunami?

Strong earthquakes generated at the ocean floor may cause displacement of large volume of water and launch big waves