3. -It is measured on the Richter scale: each
point is actually ten times greater than the
one below it. That means an earthquake
which registers 6 on the scale is ten times
greater than one measuring 5, and one
hundred times greater than one measuring 4.

4. Volcanoes form where:

5. Where do volcanoes occur?

6. Types of Crust

7. Plates:
They float, like rafts, on the
molten (semi-solid) mantle

9. -It is when oceanic crust moves towards continental
crust, for example the Nazca Plate moving towards the South
American Plate.
-As the oceanic crust is heavier it is forced downwards. As it
is forced, downwards pressure increases which can trigger
extremely violent earthquakes. At the same time the heat
produced by friction turns the descending crust back into
liquid rock called magma. The hot magma tries to rise to the
surface. Where it succeeds there will be violent volcanic
eruptions.

11. Constructive Margins

15. Measures to reduce the effects of
tsunamis are usually in two parts:
1-Predict where and when the event might happen.
2-Prepare local people and emergency services for the
disaster should it occur.
Why are there volcanic eruptions
in Philippines?

19. Why live in a danger zone?
-Good soil: Volcanic rocks break down to form some of the
most fertile soils on Earth
-Tourism: To watch eruptions, geysers, sand baths…
-Geothermal energy: Heat from the Earth can be used to
generate electricity
-Valuable raw materials: Gold, silver, copper and other
useful minerals are found in the remains of extinct
volcanoes