Volcanos

Question 1

What is the Richter Scale

Answer 1

The scale used to measure the amount of power released during an earthquake

Question 2

What is an active volcano?

Answer 2

An active volcano has either recently erupted or is going to in the future

Question 3

What is a dormant volcano?

Answer 3

Dormant volcanoes are volcanoes that have not erupted in a long time but are expected to erupt again in the future

Question 4

What is an extinct volcano?

Answer 4

An extinct volcano is never expected to erupt again

Question 5

What is a destructive plate margin?

Answer 5

A destructive plate margin usually involves an oceanic plate and a continental plate.

The plates move towards one another and this movement can cause earthquakes

Question 6

What is a constructive plate boundary?

Answer 6

Occurs when plates move apart.

Volcanoes are formed as magma wells up to fill the gap and eventually new crust is formed

Question 7

What is a conservation plate boundary?

Answer 7

When 2 plates rub against each other either in the same or a different direction at different speeds, causing friction between them

Question 8

Where is the Mariana Trench?

Answer 8

In the Western Pacific, east of the Philippines

Question 9

What is the Mariana Trench?

Answer 9

The deepest oceanic trench on Earth, it was formed by a process called subduction

Question 10

What is the focus?

Answer 10

The place inside Earth’s crust where an earthquake originates

Question 11

What is the epicentre?

Answer 11

The place on the earth’s surface which is the shortest distance directly above the focus.

The place where the maximum intensity of the earthquake is felt.

Question 12

What is a tsunami?

Answer 12

A large wave which is caused when an underwater earthquake sends shockwaves through the water, causing a surge of water to move towards the coastline

Question 13

What is a tectonic plate?

Answer 13

The large sections of rock which make up the crust of the earth.

1. Continental plates (thick plates that form at land masses)
2. Oceanic plates (thinner and form at the bottom of ocean floors).

Question 14

What is a subduction zone?

Answer 14

where the oceanic plate is pushed underneath the continental plate.

The movement of the plate downwards creates a subduction zone

huge amounts of friction mean that earthquakes take place.

Question 15

What is a seismograph?

Answer 15

An instrument used to measure the intensity of seismic waves during an earthquake

Question 16

What is the earth’s surface called?

Answer 16

The crust

Question 17

What is the Ring of Fire?

Answer 17

Place on Earth where volcanoes are most common.

A horse-shoe shaped line located around the edge of the Pacific Ocean, spanning 25,000 miles.

Home to at least 452 volcanoes, which is around 75% of all volcanoes on the planet.

Question 18

What is a divergent plate boundary?

Answer 18

When two tectonic plates move away from each other.

Along these boundaries, earthquakes are common.

Magma (molten rock) rises from the Earth’s mantle to the surface, solidifying to create new oceanic crust

Question 19

Name three composite volcanoes

Answer 19

Mount Fuji in Japan,
Mount Hood in Oregon
Mount St. Helens in Washington

Question 20

What are composite volcanoes?

Answer 20

Composite volcanoes are tall, symmetrically shaped.

Built of alternating layers of ash and lava

Acidic lava, which is very viscous (sticky).

Steep sides as the lava doesn’t flow very far before it solidifies.

Violent eruptions.

Longer periods between eruptions.

Also called Stratovolcanoes

Question 21

Name 3 advantages of living near a volcano

Answer 21

1. Geothermal energy from volcanoes can be used to heat homes and to create electricity
2. Soil on the surrounding slopes is rich and fertile which makes the area a good place to farm
3. People are protected from floods as volcanic rocks absorb rainwater

Question 22

Explain three ways volcanic eruptions can be predicted

Answer 22

1. Scientists can use seismic or earthquake waves to show if a volcano is getting ready to erupt
2. Monitoring gases escaping from a volcano using robots called Spiders – often there is an increased release of sulphur dioxide near an eruption
3. Measuring temperature - volcanoes become hotter when magma starts to rise through the main vent

Question 23

What are seismic waves?

Answer 23

Large waves of energy that flow outward through the Earth’s crust, like ripples in a pond.

The waves cause a sudden, often violent shaking of the ground.

Question 24

What are the primary impacts of an earthquake?

Answer 24

1. People killed and injured.
2. Property, buildings and homes destroyed.
3. Bridges, roads, ports and railways destroyed.
4. Gas and water pipes and electric cables are broken

Question 25

Secondary impacts of an earthquake…

Answer 25

Tsunamis and landslides hours after the event

Burst water pipes lead to a shortage of fresh water, poor sanitation and illness.

Fires starting due to broken gas pipes and fallen electricity cables.

Question 26

Name a hazard of a composite volcano

Answer 26

1. Violent eruptions produce a lot of volcanic fragments

Question 27

Where are composite volcanoes found?

Answer 27

On destructive plate margins, where the oceanic crust sinks beneath the continental crust.

Question 28

Where are shield volcanoes found?

Answer 28

On constructive plate margins, where two plates move away from one another.

Question 29

Characteristics of a shield volcano?

Answer 29

Basic lava, which is non-acidic and very runny

Gentle sides as the lava flows for long distances before it solidifies

No layers, as the volcano just consists of lava

Less violent eruptions

Shorter periods between eruptions

Question 30

Name 3 negative effects of volcanoes

Answer 30

Volcanoes are dangerous. They can kill people and damage property.

Economic activity can suffer as it is hard for businesses to operate after an eruption.

Habitats and landscapes are damaged by lava flows.

Question 31

What is the magma chamber?

Answer 31

Where the molten rock is stored beneath the ground

Question 32

What is the crater?

Answer 32

Found at the top of the volcano, where the magma erupts from

Question 33

What is the main vent?

Answer 33

The channel through which magma travels to reach the Earth’s surface

Question 34

What is the secondary vent?

Answer 34

Where some magma may escape through the side of the volcano, particularly if the main vent becomes blocked

Question 35

Where do volcanoes form?

Answer 35

Usually form along plate margins, where crustal plates are either moving towards or away from one another

Question 36

What is the constructive margin?

Answer 36

Where two plates move away from one another. Magma rises up to fill the gaps in between.

Question 37

What is the destructive margin?

Answer 37

Where two plates move towards one another.

The oceanic crust sinks beneath continental crust at a subduction zone - a point where one crustal plate is forced beneath another.

As the oceanic crust sinks into the mantle it creates magma, which rises to form a volcano

Question 38

Why do volcanoes affect different places in different ways?

Answer 38

They cause more damage in poorer countries, where there are fewer resources to predict and prepare for them.

Question 39

What is a pyroclastic flow?

Answer 39

A mixture of hot steam, ash, rock and dust (from composite volcanoes).

Can roll down the sides of a volcano at very high speeds and with temperatures of over 400°C

Question 40

Name two places where you can find shield volcano

Answer 40

1. Mauna Kea in Hawaii, USA
2. Galapagos islands

Question 41

Who proposed the theory of continental drift?

Answer 41

German scientist Alfred Wegener