Live with tectonic hazards revision-GCSE

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1. Living with tectonic hazards
Why are earthquakes and
volcanoes found in particular
places?

2. What are Tectonic Plates?
•The Earth’s crust
is divided into
large blocks called
plates. The heat
inside the Earth
creates currents
which move the
plates around.
•Oceanic plates
carry the oceans.
•Continental plates
carry the
continents.
The movement of plates is called
Plate Tectonics

3. The Earth’s major plates and plate boundaries

4. What happens where plates meet?
•The places where
plates meet are called
plate margins or
boundaries. It is often
in these places that
the Earth is unstable
resulting in
earthquakes and
volcanoes.

5. What are the different types of plate
margins (boundaries)?
Boundaries between tectonic plates can be
of three types. Click on the links to view
animations of each plate boundary.
1. Constructive plate boundaries create
new crust, and often give rise to volcanoes
and earthquakes.
2. Destructive plate boundaries create
mountains and may give rise to volcanoes
and earthquakes.
3. Conservative plate boundaries do not
create or destroy land, but often give rise
to earthquakes (not volcanoes).
Key Words
Oceanic
Continental
Friction
Earthquakes
Magma
Volcanoes
Subuction
Fold Mountains

6. What are earthquakes and volcanoes?
Earthquakes
•Occur when plates are
moving towards or alongside
each other e.g. the
conservative plate margin at
the San Andreas Fault in
California, USA
•Pressure build up until there
is a sudden movement,
sending a shockwave
through the Earth’s crust
•Focus – point where the
shockwaves start
•Epicentre – the point above
the focus on the Earth’s
surface
Volcanoes
•Form when semi-molten
rock (magma) rises to the
Earth’s surface. When the
magma reaches the
Earth’s surface it
becomes lava.
Vibrations during an earthquake
are measure using a seismometer
this produces a seismograph.
The Richter scale measure the
energy released on a scale of 1 to
10.

7. What are the different types of
volcano?
Example
Mount
St Helens

8. Living with tectonic hazards
Why do the effects of Tectonic
Hazards Vary?

9. Why do effects of tectonic hazards vary?
The effects of tectonic
hazards vary because
1.Some places are
nearer to the source
of earthquakes or
volcanoes
2.Some places are
better prepared than
others
3.Some places have
more resources to
deal with the effects of
the hazard
Primary effects
Immediate effects
•Death/injury
•Loss of land/buildings
•Damage to infrastructure
Secondary effects
Longer term effects
•Lack of shelter
•Poor water/food supply
•Loss of income
•Long-term damage to infrastructure

10. Kobe Earthquake - Japan
M
ED
C

11. Gujarat Earthquake - India
LED
C
You may be asked to
compare impacts between
MEDCs and LEDCs

12. Mt St Helens – USA (causes)
•Erupted on the morning
of May 18th 1980, after
being inactive for over
120 years.
•Caused by the
subduction of the oceanic
Juan de Fuca plate under
the continental North
American plate, on the
West Coast of the United
States. The volcano
forms part of the Rockies
Range of mountains.

13. Mt St Helens – USA (effects)

14. Why do people live in hazardous areas?
•People feel that it “won’t happen to them” and that they
are well prepared
•Some areas like California (USA), have an excellent
climate, superb beaches and a wide range of job
opportunities
•In places like Iceland, geothermal energy can be
generated from the volcanic rocks
•Many minerals and precious stones are found in volcanic
areas
•Volcanic rock provide mineral-rich fertile soil, which is
excellent for agriculture
•Volcanic soil is often found in spectacular areas of
scenery which provide an excellent opportunity for the
development of tourism.

15. Living with Tectonic Hazards
How can the risk of tectonic
activity been reduced?

16. Preparing for Earthquakes
•It is very difficult if not impossible to predict earthquakes
•Therefore it is more worthwhile to invest money and resources in preparing
for earthquakes
•MEDCs tend to prepare better for earthquakes than LEDCs

17. Predicting Volcanic Eruptions
As a volcano becomes active, it gives off a number of warning
signs. These warning signs are picked up by volcanologists
(those who study volcanoes) and the volcano is monitored.

18. Preparing for Volcanic Eruptions
A detailed plan is needed for dealing with a possible eruption.
Everyone who could be affected by the eruption needs to
know the plan and what they should do if it needs to be put
into action.
•Planning for a volcano includes creating an
exclusion zone around the volcano
•Being ready and able to evacuate residents
•Having an emergency supply of basic provisions
such as food
•Funds need to be available to deal with the
emergency and a good communication system
needs to be in place
How to prepare?

19. Why are the effects of hazards
worse in LEDCs than MEDCs?