Earthquakes and Plate Tectonics

Question 1

Give one example of a destructive plate boundary

Answer 1

Where the Nazca Plate meets the South American Plate.

Question 2

In which direction do plates move at a destructive boundary?

Answer 2

They move together. One plate may sink (subduct beneath the other) or the plates may collide causing fold mountains.

Question 3

What is a secondary effect?

Answer 3

Impacts that occur as a result of the primary effects.

Question 4

What are tectonic plates?

Answer 4

The Earth’s crust is broken into 7 major pieces which ‘float’ on the magma in the mantle. These are known as the tectonic plates.

Question 5

Where do volcanoes and earthquakes usually occur?

Answer 5

Along the lines of the plate boundaries.

Question 6

The Richter scale uses a logarithmic scale. What is this?

Answer 6

This is when each whole number increase in magnitude represents a 10 times increase in amplitude. As an estimate, each whole number step in magnitude means the release of about 31 times more energy. So a 6.1 magnitude earthquake is 10 times more powerful than a 5.1.

Question 7

Boundaries or boundarys?

Answer 7

Boundaries

Question 8

Is it enough to say that “one primary effect of an earthquake is buildings collapsing” in the exam?

Answer 8

No. Try to use specific details from a case study. E.g. “In Ecuador 2006 pyroclastic flows destroyed 7 villages on the north western slopes of the Tungurahua Volcano”.

Question 9

What causes tectonic plates to move?

Answer 9

Convection currents in the mantle cause the plates to move around 2-5cm per year (about the rate your fingernails grow).

Question 10

Which instrument measures the force of an earthquake?

Answer 10

A Seismometer

Question 11

Ricter Scale or Richter Scale?

Answer 11

Richter Scale

Question 12

What are the names of the three types of plate boundary?

Answer 12

Constructive, destructive and conservative plate boundaries.

Question 13

Earthquakes can be accurately predicted. True or false?

Answer 13

False. We cannot confidently say where or when an earthquake will strike or how strong it will be.

Question 14

What are the names of the four layers of the Earth?

Answer 14

Inner core, outer core, mantle and the crust.

Question 15

Give one example of a conservative plate boundary

Answer 15

Where the North American plate and the Pacific Plate slide past each other along the West coast of the USA.

Question 16

What is a primary effect?

Answer 16

Impacts as a direct result of the event itself.

Question 17

Gas pipes breaking is a primary effect of an earthquake. True or false?

Answer 17

True. As the earth violently shifts pipes can break. This can lead to a secondary effect such as fires.

Question 18

Which of the Earth’s layers is the thinnest?

Answer 18

The crust. Contnental crust is around 20 miles (35km) thick. Oceanic crust is newer and more dense although it is thiner at around 6 miles (10km) thick.

Question 19

What is a tsunami?

Answer 19

A large ocean wave caused by an underwater earthquake.

Question 20

In which direction do plates move at a constructive boundary?

Answer 20

They move apart. This can cause wide volcanoes and ocean ridges.

Question 21

Give an alternative to the Richter scale.

Answer 21

The Mercalli scale. This measures how much damage the earthquake caused on the surface rather than how much the Earth has moved.

Question 22

What are convection currents?

Answer 22

The Earth’s core heats magma in the mantle which rises. Eventually it moves sideways dragging the crust with it then falls back down towards the core as it cools. This process repeats in a cycle known as a convection current.

Question 23

What are foreshocks?

Answer 23

Smaller ground tremors (shaking) occuring before the main earthquake.

Question 24

Give one example of a constructive plate boundary

Answer 24

Where the Eurasian Plate moves away from the North American plate. This creates the Mid-Altlantic Ridge.

Question 25

Unemployment is a primary effect of a volcano. True or false?

Answer 25

False. Unemployment is a secondary effect caused by the primary effect of businesses being destroyed.

Question 26

What is magma?

Answer 26

Hot, molten and liquid rock beneath the surface of the Earth. Often called lava when it reaches the surface.

Question 27

In which direction do plates move at a conservative boundary?

Answer 27

They move alongside each other either in the same direction or opposite directions. This can cause powerful earthquakes.

Question 28

What are aftershocks?

Answer 28

Smaller ground tremors (shaking) occuring after an earthquake.

Question 29

What is the Richter Scale used for?

Answer 29

To measure how intense (how much shaking) the earthquake was.