1.3 Volcanoes

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1.3 Volcanism

Page 12 and 13 of the textbook.

Recap earthquakes

Check homework

Instruction
Let's practice

One piece of Earth's crust please

Plate tectonics

Convergent

Convergent

Divergent

Transform

How are earthquakes connected to plate tectonics?

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.

Did you manage to do the homework?

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

What do you know about volcanoes?

Why do volcanos occur in places where there are also earthquakes?

How does a volcano form?

Read 'How does a volcano form?' on page 12 of the textbook.

Write down in your own words how a volcano forms.

Finished early? Read 'Consequences of a volcano eruption'.

How does a volcano form?

How does a volcano form?

A volcano is formed by a series of eruptions of lava and ash.

•  rock ocean floor is pushed into mantel
•  rock melts, magma is formed
•  heated substance lighter than  surroundings
•  heated substance wants to rise
•  pressure too high: eruption
•  magma becomes lava and leaves volcano via the crater

Volcanoes in the ocean

Volcanos in the ocean:

•  two parts of ocean floor move apart
•  crack in the Earth’s crust
•  filled with hot rock (lava)
•  lava comes into contact with water
•  lava solidifies
•  a new piece of ocean floor is formed
•  mid-oceanic ridge = sort of stretched out mountain range along the ocean floor

Consequences of a volcanic eruption

What signs are there that a volcano is about to erupt?

• small earthquakes
• smoke
• swelling

• restless animals

Consequences of a volcanic eruption

What are the possible consequences of a volcanic eruption?

• Large areas become covered with ash and lava
• Extremely hot gas clouds are formed which blast from the volcano

Consequences of a volcanic eruption

Why are the consequences of a volcano different for people in rich countries than in poor countries?

• In rich countries people can signal that an eruption is going to take place more quickly and easily.
• In rich countries the population can be warned and evacuated more quickly than in poor countries.

Let's practice!

Page 12 of the workbook (or 1.3 online): 3, 4 and 6.

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 1.3: 3, 4 and 6

Next week: Camp week