1.2 Earthquakes

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1.2 Earthquakes

Page 10 and 11 of the textbook.

Recap plate tectonics

Check homework

Instruction
Let's practice

The Earth

One piece of Earth's crust please

Plate tectonics

Convergent

Convergent

Divergent

Transform

Did you manage to do the homework?

Page 8 of the workbook (or 1.1 online): 1, 2 and 4.

Formation of mountains: The Alps

Learning objective: You understand how plate tectonics formed the Alps.

The Alps

50 million years ago Italy was attached to Africa. An ocean lay between Italy and Europe.
 The Alps did not yet exist.

Earth’s crust of Africa moves to the north wherby:

• sea becomes narrower
• seabed gets jammed
• rock layers are pushed up
• The Alps are formed

What do you know about earthquakes?

How are earthquakes connected to plate tectonics?

How do earthquakes form?

West coast South America:

•  ocean floor slides under continent
•  thick layer of rock from ocean floor  is trapped under continent

What happens when pressure becomes  too great?

How do earthquakes form?

West coast South America:

•  ocean floor slides under continent
•  thick layer of rock from ocean floor  is trapped under continent

What happens when pressure becomes too great?
Ocean floor suddenly jolts and moves a
 little under the continent = earthquake!

Epicentre

The earthquake is most powerful right above the place where the ocean floor was jammed. That is called the epicentre.

The Richter Scale indicates the strength of the earthquake. The scale goes from 1 (weak)
tot 12 (strong).

An earthquake with a scale of 6 is 10 times stronger than a quake of 5, and 100 times stronger than a quake of 4.

Damage

What damage can an earthquake cause?

• buildings collapse
• people trapped under rubble
• gas pipes and electricity lines broken
• fires

Damage

Why can the consequences of an earthquake be different for rich and poor countries?

Damage

In rich countries there is more money and knowledge to build earthquake resistant buildings than in poor countries, therefore fewer buildings collapse. That is why there are fewer victims in earthquakes in rich countries than in poor countries. People in rich countries have more belongings and therefore the financial damage is often greater in rich countries than in poor countries.

Let's practice!

Page 10 of the workbook (or 1.2 online): 1, 3 and 7.

How do you call the outer layer of the Earth?

1. Outer Earth
2. Continent
3. Earth's crust
4. Outer mantle

How do you call the movement of the tough rock within the Earth's mantle?

1. Currents
2. Magma currents
3. Plate tectonics
4. Convection currents

Next week

Homework:

Paragraph 1.2: 1, 3 and 7

Next week: 1.3 Volcanism