Slides in this set
Structure of the Earth
The Earth is made up of four distinct layers:
· The inner core is in the centre and is the hottest part of the Earth. It is
solid and made up of iron and nickel with temperatures of up to 5,500°C.
With its immense heat energy, the inner core is like the engine room of
· The outer core is the layer surrounding the inner core. It is a liquid layer,
also made up of iron and nickel. It is still extremely hot, with temperatures
similar to the inner core.
· The mantle is the widest section of the Earth. It has a thickness of
approximately 2,900 km. The mantle is made up of semi-molten rock
called magma. In the upper parts of the mantle the rock is hard, but lower
down the rock is soft and beginning to melt.
· The crust is the outer layer of the earth. It is a thin layer between 0-60 km
thick. The crust is the solid rock layer upon which we live.
There are two different types of crust: continental crust, which carries land,
and oceanic crust, which carries water.…read more
Distribution of Tectonic Activity
· Earthquakes are most likely to · Volcanoes are most likely to occur
occur either on or near plate either on or near plate
· Occur in long, narrow bands · Occur in long, narrow bands
(largest of which runs along the (largest of which is the Pacific
Pacific Ocean) Ocean Ring of Fire)…read more
· Hotspots are another place where volcanoes occur.
· They are fixed points in the mantle which generate
heat. Usually occur under the ocean.
· The intense heat causes a build-up of pressure and
magma erupts through the crust.
· If the magma rises above the ocean surface a volcano
· Hotspots usually create chains of volcanic islands, for
example, Hawaii. Hawaii is in the pacific ocean and
consists of five connected volcanic mountains .…read more
At a constructive plate boundary the plates
Constructive move apart. This is because of convection
currents. When the plates move apart magma
Plate Boundary rises from the mantle and this forms a volcano.
o The plates move away from
(This is also accompanied by earthquakes)
each other and create the
crust. (Also known as When the magma reaches the surface, it cools
Divergent) and solidifies to form a new crust of igneous
rock. This process is repeated many times, over
o An example of a constructive a long period of time.
plate boundary is Iceland.
o They are often found under
the sea and the chain of
undersea mountains formed
are known as a mid-ocean