Plate Tectonics 🍽🌏

Question 1

Name the four LAYERS of the Earth:

Answer 1

> Crust
Mantle
Outer Core
Inner Core

Question 2

What are the 2 types of CRUST and what are they like?

Answer 2

The two types of crust are:
> Oceanic
> Continental

The Earth’s crust is quite thin, as little as 3 miles under the oceans, but it is much thicker under the continents, about 25 miles. So, we talk about Oceanic and Continental

Question 3

Explain CONVECTION CURRENTS and how this effects the movement if the plates:

Answer 3

The plates float on the mantle and are made to move by convection currents

Convection currents rise up from particular hotspots near the core. As the molten magma of the mantle moves, so the plates are carried with it

Question 4

Give a brief description of the CRUST:

Answer 4

It ‘floats’ on the surface, at the top

Question 5

Give a brief description of the MANTLE:

Answer 5

A hot layer of semi-solid rock below the crust

Question 6

Give a brief DESCRIPTION of the core(s) of the Earth:

Answer 6

At the centre of the Earth is the core. This is made up of two distinct parts; a thick liquid OUTER layer and a solid INNER CORE

Question 7

Give a description of a DESTRUCTIVE plate boundary:

Answer 7

> The crusts involved are: OCEANIC and CONTINENTAL
When they meet, the Oceanic gets pushed down as it’s
HEAVIER
The point where this happens is called the SUBDUCTION zone
This leads to the formation of an OCEAN TRENCH
The FRICTION caused when it sinks can create huge earthquakes
The crust re-melts and gets forced upwards, due to pressure, to
form a volcano

Question 8

Give a description of a CONSTRUCTIVE plate boundary:

Answer 8

> Plates which move away from each other are known as
DIVERGING plates
Magma forces its way to the surface to fill the gap created
These creates, or constructs new land once cooled
This may result in the development of underwater volcanoes and
ridges of land
The most famous example is ‘the Mid-Atlantic Ridge’

Question 9

Give a description of a CONSERVATIVE plate boundary:

Answer 9

> This is when plates slide past each other
No crust is MADE or DESTROYED
When plates get stuck, friction builds up and eventually ‘jump’ free
unable to cope with the stress
This causes an EARTHQUAKE

Question 10

Give a description of COLLISION plate boundary:

Answer 10

> Both plates are the SAME type of crust
They are both EQUAL in weight, meaning neither can sink
The plates crash together and start to be FORCED upwards
This creates FOLD mountains

Question 11

What is the definition of a VOLCANO?

Answer 11

A volcano is an opening, or rupture, in a planet’s surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface

Question 12

What are the 3 different types of VOLCANO?

Answer 12

> Active
Dormant
Extinct

Question 13

What is an ACTIVE volcano?

Answer 13

One which is liable to erupt at any time

eg. Mount Etna

Question 14

What is a DORMANT volcano?

Answer 14

One which has not erupted for many years

eg. Mount Pinatubo

Question 15

What is an EXTINCT volcano?

Answer 15

One which has not erupted in a VERY long time and is unlikely to erupt again

eg. Mount Kulal

Question 16

Name 3 BENEFITS of living near a volcano:

Answer 16

> Energy can be sourced from Geothermal energy
Rocks provide building materials and resources
Water boiled underground produces a gas which can generate
electricity

Question 17

Name 2 PROBLEMS with living near a volcano:

Answer 17

> It can be very dangerous
Volcanic landslides can destroy buildings
Lava pollutes rivers and then burns down trees and houses in
its path

Question 18

What is a TSUNAMI?

Answer 18

A TSUNAMI is a series of ocean waves that send surges of water, sometimes reaching height of over 100 feet, onto land. The ‘walls of water’ can cause widespread destruction when they crash ashore

Question 19

What causes TSUNAMIS?

Answer 19

They are caused typically by undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly, it displaces the water above it and launches the rolling waves that will become the TSUNAMI

Question 20

How fast do TSUNAMIS travel?

Answer 20

TSUNAMIS race across the sea at up to 500 miles per hour; about as fast as a jet aeroplane. At that pace they can cross the entire expanse of the Pacific Ocean in less than a day

Question 21

How can we ‘prevent’ TSUNAMIS?

Answer 21

The best defence against any TSUNAMI is early warning that allows people to seek HIGHER ground. Seismic equipment can be used to identify TSUNAMIS at sea, then the Warnung can be given

Question 22

What is an EARTHQUAKE?

Answer 22

> An EARTHQUAKE is caused by a sudden movement between
the plates
The ground shakes suddenly, due to a piece of the Earth’s crust
having moved
This produces very strong shockwaves that travel out from the
centre of the crust

Question 23

What is the ‘FOCUS’ of an earthquake?

Answer 23

The FOCUS is the point where the earthquake STARTS. The waves spread out from the FOCUS. Near the FOCUS, the waves are stronger and more damage occurs

Question 24

What is the ‘EPICENTRE’?

Answer 24

The EPICENTRE is the point on the Earth’s surface immediately ABOVE the FOCUS

Question 25

How do we MEASURE an earthquake?

Answer 25

> The SEISMOGRAPH measures the shockwaves, or seismic
waves
The RICHTER SCALE measures the strength of the earthquake,
or the energy released
The MERCALLI SCALE measures the intensity

Question 26

What are the 2 SHORT TERM effects of an earthquake?

Answer 26

> Landslides may occur and Tsunamis may cause flooding in
coastal areas

> People may be killed or injured, homes destroyed, communication
links disrupted, water pipes burst and water supplies may be
contaminated

Question 27

What are the 2 LONG TERM effects of earthquakes?

Answer 27

> Shops and businesses may be destroyed. The damage to
transport and communication links can make trade difficult
and businesses may take a long time to recover from this

> The cost of rebuilding a settlement is high and could take years.
Investment in the area may only be focused on repairing the
damage of the earthquake. Income could be lost