Tectonics

Question 1

Earthquake

Answer 1

The violent shaking of the earth’s crust.

Question 2

Earthquake magnitude

Answer 2

The strength of an earthquake.

Question 3

Earthquake intensity

Answer 3

The violence of earth’s movements produced by an earthquake.

Question 4

Mercalli Scale

Answer 4

The scale used to measure earthquake intensity (I to XII)

Question 5

Richter Scale

Answer 5

The scale used to measure earthquake magnitude

Question 6

Focus

Answer 6

The point in which the pressure is released inside the earth. Often many kilometres down.

Question 7

Epicentre

Answer 7

The point on the ground surface directly above the focus. Where the greatest damage usually occurs.

Question 8

Crust

Answer 8

The outer layer of the earth. 0-100km thick

Question 9

What is the difference between continental crust and oceanic crust?

Answer 9

Oceanic:
Thinner
Newer
Basalt
More dense

Continental:
Thicker
Older
Granite
Less dense

Question 10

Mantle

Answer 10

The third layer in the earths structure, 100km-2900km deep. Made of molten rock.

Question 11

Outer core

Answer 11

Second layer in the earths structure, 2900km-5100km thick. Made of liquid iron and nickel.

Question 12

Inner core

Answer 12

5100km-6378km deep, first layer of the earth.

Question 13

Convection currents

Answer 13

Heated plumes of magma which create crustal plate movement.

Question 14

What happens when convection currents diverge and converge?

Answer 14

When they diverge, plates move apart.

When the converge, plates move towards each other.

Question 15

Plates

Answer 15

Pieces of the earth’s crust

Question 16

Plate boundary

Answer 16

The point where two tectonic plates meet.

Question 17

How many major and minor plates are there?

Answer 17

7 major and 8 minor

Question 18

Where do most of the world’s earthquakes and volcanoes occur?

Answer 18

On or near the plate boundaries.

Question 19

Hotspots

Answer 19

Areas away from plate boundaries where volcanoes and earthquakes are found.

Question 20

Where can you find hotspots?

Answer 20

In places where the crust is very thin

Question 21

Give an example of where a hotspot is.

Answer 21

Hawaii

Question 22

Where is the largest concentration of volcanoes found and what is its name?

Answer 22

The Pacific Ocean - The Ring of Fire.

Question 23

What are the 7 major plates called and where are they found?

Answer 23

Question 24

Magma Chamber

Answer 24

Large underground pool of magma

Question 25

Lava

Answer 25

Magma once it reaches the surface

Question 26

Crater

Answer 26

Bowl shaped basin on the top of the volcano.

Question 27

Vent

Answer 27

Central tube which magma travels through

Question 28

Secondary cones

Answer 28

Eruptions from other vents may build up secondary cones on the flanks.

Question 29

Ash/steam/gas

Answer 29

Material thrown out by the force of the eruption.

Question 30

Volcanic bombs

Answer 30

Larger material thrown out by the force of the eruption.

Question 31

How are some ways experts can estimate when an eruption is likely to happen?

Answer 31

Seismometers - an instrument that measures ground vibrations caused by a variety of processes.

Gas sensors - an instrument that detects carbon dioxide, sends data continuously via radio to an observatory.

Tilt-meters - when magma accumulates beneath the ground, the slope of adjacent areas will usually tilt away from the centre of uplift.

GPS satellites - detect motion at a volcano before any earthquakes occur.

Question 32

How are some ways you can prepare for volcanic eruptions?

Answer 32

Evacuation - evacuating all the citizens before the volcano erupts.

Diverting the lava flow - changing the course of the lava to avoid areas of value.

Go bags - a bag of things you need to take in the case of an evacuation.

Question 33

What are responses?

Answer 33

How countries and communities react to tectonic hazards and other disasters.

Question 34

What are the two categories of responses?

Answer 34

Short-term/immediate - a response in days or weeks immediately after a disaster has happened. Short-term responses mainly involve search and rescue, helping the injured and providing key supplies.

Long-term - responses go on for months and years after a disaster. It involves rebuilding destroyed houses, schools, hospitals, etc. It also involves kick-starting the local economy.

Question 35

What are the three types of impacts?

Answer 35

Social - direct impact on people.
Economic - impact on economic activities such as businesses.
Environmental - impact on the landscapes including water and air pollution.

Question 36

Describe what happens on a constructive margin.

Answer 36

When plates move apart, magma from the mantle rises to construct new land in the form of a shield volcano.

Question 37

Describe what happens on a destructive margin.

Answer 37

Usually involving an oceanic plate and a continental plate, they move towards each other, and at the collision, the oceanic plate subducts as it is denser. The plate melts in the mantle to form magma, which then escapes ad rises through a composite volcano (formed).

Question 38

Describe what happens on a conservative margin.

Answer 38

The plates are moving past each other or are moving side by side at different speeds. Friction occurs and the plates get stuck. Pressure builds up, and when the pressure is released, it sends out huge amounts of energy causing an earthquake.

Question 39

Describe what happens on a collision boundary.

Answer 39

Involving two continental plates, neither can sink so the goo upwards to form fold mountains. Earthquakes can occur.