Science - Tectonic plates

Order of layers of the Earth

crust, upper mantle, lower mantle, outer core, inner core

Crust

Outermost layer of the Earth, is made out of thin rock. 2 types: continental and oceanic

Upper/Lower mantle

Earth’s middle layer

Outer core

Fluid layer outside the inner core made of iron and nickel

Inner core

Innermost layer of inner and outer core, is solid due to high pressure

Lithosphere

Earth’s outer zone made up of rock. Consists of the crust and upper mantle

Asthenosphere

The thin zone just below the lithosphere, is hotter and weaker and acts like magma

Continental drift

The movement of continents due to tectonic plates seperating over time

The man who published the theory of continental drift

German meteorologist Alfred Wegner

Origins of Alfred Wegner’s theory

In 1912, Alfred noticed that South America’s and Africa’s Eastern coasts fit like a puzzle

Urkontinent

Super continent

Pangea

All-Earth, continents were connected for 160,000,000 years

Mountains that are about 500,000,000 years old

Highlands, Little Atlas mountains and Appalachian mountains

When did Himalayas begin forming

50,000,000 years ago

Convection

The motion of a fluid in response to heat. As a liquid gets hotter, it rises while cooler liquid floats down

Seafloor spreading

When the seafloor starts to seperate, molten magma rises from the mantle and creates new oceanic crust

What happens when 2 oceanic plates seperate

Rifts and valleys form along ocean ridges

Subduction

When 1 tectonic plate converge underneath another, due to converging plates. Oceanic is more dense and sinks underneath

What forms when 2 oceanic plates/continental-oceanic plates collide

Forms volcanoes

Types of subduction

Continental-oceanic or oceanic-oceanic

Convergant boundary

When 2 plates collide towards each other

Properties of convergent boundaries

Can be subduction, slow movement, can create mountains, high areas of earthquakes

Divergent boundary

When 2 tectonic plates get pulled and seperated

Properties of divergent boundary 

Can be seafloor spreading, can create volcanoes, weak earthquakes

Rift

The zone where divergent boundaries occur

Transform boundary

When 2 tectonic plates slide across each other

Properties of transform boundary

Can cause earthquakes, areas are also called faults

Volacno

A rupture in the Earth’s crust which can release magma, volcanic rock, ash and gas

Ring of fire

75 volcanoes around the boundary of the Pacific Plate

How many volcanoes are around the world

600+ volcanoes, 50 erupt per year

Earthquakes

A buildup of pressure and release of energy at the Earth’s crust

Epicentre

The point on the Earth’s surface above the focus

Focus

The point under the crust where Earthquakes originate

Intensity

Measure of destruction of an earthquake

Magnitude

Measure of energy released of an earthquake

Moment magnitude scale

A logarithmic scale used to compare energy released by earthquakes

Tsunami

A long, high sea wave caused from earthquakes

Seismogram

A record of the seismic from an earthquake, measured with a seismograph or seismometer

Properties of primary waves

Fastest seismic wave, longitudinal, travels through solids, liquids and gases