Volcanoes

Question 1

What type of slope does a shield volcano have?

Answer 1

Gentle slopes built from previous eruptions.

Question 2

What type of lava is released by shield volcanoes?

Answer 2

Runny lava

Question 3

How often do shield volcanoes erupt?

Answer 3

Frequent eruptions

Question 4

Are shield volcano eruptions mild or severe?

Answer 4

Mild

Question 5

What are the slopes of composite volcanoes like?

Answer 5

They have steep sides.

Question 6

What type of volcano can be found at hotspots?

Answer 6

Shield

Question 7

How are seamounts formed?

Answer 7

Extinct volcanoes apply too much pressure on the crust so subsidence occurs. This, combined with erosion creates sea mounts.

Question 8

What type of volcano is found at subduction zones?

Answer 8

Composite

Question 9

What type of volcano is found at constructive plate boundaries?

Answer 9

Shield

Question 10

How do volcanoes form at destructive plate boundaries?

Answer 10

When the oceanic plate melts in the subduction zone, plutons of magma rise to create volcanoes.

Question 11

How do volcanoes form at oceanic ridges?

Answer 11

They occur as a result of sea floor spreading as magma rises through gaps in the crust and makes its way to the surface.

Question 12

What type of lava is found at oceanic ridges?

Answer 12

Low viscosity, balsatic lava

Question 13

How do volcanoes form at rift valleys?

Answer 13

When the crust drops down, the magma rises through the gaps as the crust becomes thinner.

Question 14

What is meant by the term “active”?

Answer 14

An eruption is currently going on

Question 15

What is meant by the term “dormant”?

Answer 15

It has not erupted in the last 2000 years

Question 16

What is meant by the term “extinct”?

Answer 16

The volcano will not erupt again.

Question 17

Give an example of an active volcano

Answer 17

Mauna Loa, Hawaii

Question 18

Give an example of a dormant volcano

Answer 18

Mt Rainier, USA

Question 19

Give an example of an extinct volcano

Answer 19

Mount Snowden, Wales

Question 20

Where are shield volcanoes found?

Answer 20

Hotspots and constructive boundaries

Question 21

What are composite volcanoes made of?

Answer 21

Alternating layers of ash and lava from previous eruptions.

Question 22

What are shield volcanoes made of?

Answer 22

Lava

Question 23

Where are composite volcanoes found?

Answer 23

Destructive plate boundaries

Question 24

What are eruptions of composite volcanoes like?

Answer 24

Pyroclastic flows

Question 25

What are eruptions of shield volcanoes like?

Answer 25

Lava flows

Question 26

What is lava made of?

Answer 26

Silicon, oxygen, aluminium, iron, magnesium, calcium, sodium, potassium, phosphorus, and titanium

Question 27

How do high viscosity lavas flow?

Answer 27

Slowly

Question 28

How far do high viscosity lavas flow?

Answer 28

They cover small areas.

Question 29

How do low viscosity lavas flow?

Answer 29

Quickly

Question 30

How far do low viscosity lavas flow?

Answer 30

They cover thousands of square kilometres

Question 31

Why do low viscosity lavas not result in violent eruptions?

Answer 31

Gases are allowed to escape so pressure does not build up.

Question 32

Why do high viscosity lavas lead to violent eruptions?

Answer 32

Gas pressures build up.

Question 33

What is the character of volcanoes largely controlled by?

Answer 33

The viscosity of the lava.

Question 34

How is the magnitude of volcanoes measured?

Answer 34

Using the VEI

Question 35

What does VEI stand for?

Answer 35

Volcanic Explosivity Index

Question 36

What is the VEI measured on a scale of?

Answer 36

0-8

Question 37

What does a VEI score of 0 suggest?

Answer 37

Non-explosive

Question 38

What does a VEI score of 8 suggest?

Answer 38

Very large

Question 39

Why might eruptions with the largest VEI scores not have the worst effects?

Answer 39

Volcano could be in a rural area with a small population Prediction and evacuation LIC/HIC Population density

Question 40

List 4 potential primary impacts of volcanic eruptions

Answer 40

Tephra Volcanic gases Lava flows Pyroclastic flows

Question 41

What is tephra?

Answer 41

Solid material of varying size that ranges from volcanic bombs to ash, all ejected into the atmosphere.

Question 42

What are the volcanic gases released by volcanoes?

Answer 42

CO2, CO, SO2, CL2 and hydrogen sulfide

Question 43

Give an example where volcanic gases have caused a problem

Answer 43

In 1986, CO2 emissions from a lake in the crater of Nayos, Cameroon killed 1700 people.

Question 44

What are lava flows?

Answer 44

Streams of molten rock that pour from an erupting vent

Question 45

What are pyroclastic flows?

Answer 45

Very hot, gas charged, high velocity flows made up of a mixture of gas and tephra.

Question 46

Give an example where pyroclastic flows have caused problems in the past

Answer 46

Pompeii was destroyed by pyroclastic flows from Mt Vesuvius in 79AD.

Question 47

What are 6 potential secondary impacts of volcanic eruptions?

Answer 47

``` Lahars Flooding Volcanic landslides Tsunamis Acid rain Climate change ```

Question 48

What are lahars?

Answer 48

Melted snow and ice as a result of the eruption combined with volcanic ash forms mud flows that can move down the course of river valleys at high speeds.

Question 49

Give an example of a deadly lahar

Answer 49

1985, a lahar destroyed the Columbian town of Armero after Nevado Del Ruiz erupted, only 25% of the population survived.

Question 50

Why can flooding occur after an eruption?

Answer 50

The eruption may melt glaciers and ice caps.

Question 51

When has flooding as a result of an eruption been a problem?

Answer 51

Iceland 1996, after the Grimsvotn volcano erupted.

Question 52

What are volcanic landslides?

Answer 52

Large masses of wet/dry rock and soil that fall, slide or flow rapidly under the force of gravity.

Question 53

What are volcano-related tsunamis caused by?

Answer 53

Violent volcanic eruptions

Question 54

Give an example when a tsunami caused by an eruption has been deadly

Answer 54

Krakatoa, Indonesia 1883, estimated 36,000 dead

Question 55

Why can eruptions cause acid rain?

Answer 55

Volcanic gases released containing sulphur mix with atmospheric moisture.

Question 56

Why can eruptions cause climate change?

Answer 56

Volcanic debris can reduce global temperatures.

Question 57

What are the 3 methods of mitigation?

Answer 57

Preparation, prevention and adaptation

Question 58

What visual change can suggest a volcano may erupt?

Answer 58

Ground deformation

Question 59

What do seismometers detect?

Answer 59

Small earthquakes

Question 60

What are the small earthquakes caused by? (In a volcanic context)

Answer 60

Magma rising up through cracks in the Earth's crust

Question 61

What do thermal imaging techniques and satellites detect?

Answer 61

Rising temperatures as volcanic activity increases.

Question 62

What are gas samples and chemical sensors used for?

Answer 62

Detecting high sulphur levels which may indicate that the volcano will erupt soon.

Question 63

What are long-period events?

Answer 63

These indicate the movement of magma as a result of increased pressure on the rock and can be seen on seismometer readings.

Question 64

How many lives did the knowledge of long-period events save when Popocatepetl erupted?

Answer 64

30,000

Question 65

When did Popocatepetl erupt?

Answer 65

2000

Question 66

Where is Popocatepetl?

Answer 66

Mexico

Question 67

How do you spell the name of the Icelandic volcano that erupted in 2010?

Answer 67

Eyjafjallajokull

Question 68

What did the volcanic ash cloud released by Eyjafjallajokull in 2010 cause?

Answer 68

Flights in and out of the UK to be cancelled.

Question 69

Were there any deaths when Eyjafjallajokull erupted?

Answer 69

No

Question 70

What is expected for Eyjafjallajokull in the future?

Answer 70

Larger eruptions

Question 71

Tectonic plate boundaries are home to what percentage of volcanoes?

Answer 71

80%

Question 72

What type of plate boundary is Iceland on?

Answer 72

A constructive plate boundary?

Question 73

What is significant about Iceland's location on a constructive plate boundary?

Answer 73

It will continue to grow

Question 74

What are 5 ways in which people can adapt for volcanic eruptions?

Answer 74

``` Monitoring systems Redrafted action plans Relocation Building techniques Concrete shelters ```

Question 75

How can building techniques be used to mitigate the risks from volcanic eruptions?

Answer 75

Retrofit buildings | Stronger structures

Question 76

What are redrafted action plans based on?

Answer 76

Previous events

Question 77

What are 6 ways in which death and destruction by volcanic eruptions can be prevented?

Answer 77

``` Location of infrastructure Building techniques Lava channels Warning systems Evacuation Evacuation routes ```

Question 78

Where should businesses/schools and homes be built?

Answer 78

Away from volcanoes

Question 79

What type of building should be strategically placed?

Answer 79

Hospitals

Question 80

What do lava channels do?

Answer 80

Redirect lava away from buildings and people

Question 81

Why are clear evacuation routes important?

Answer 81

They can save lives and reduce the number of injuries.

Question 82

What are 7 ways in which people can prepare for volcanic eruptions?

Answer 82

``` Emergency funds Emergency supplies Hazard maps Evacuation Exclusion zones Communication systems Education ```

Question 83

What do hazard maps show?

Answer 83

Pathways of expected eruption products

Question 84

What is important when planning an evacuation?

Answer 84

That there are places to temporarily relocate people.

Question 85

What is a benefit of exclusion zones?

Answer 85

They reduce disruption

Question 86

Why are communication systems important?

Answer 86

For coordinating rescue and give warnings or evacuation orders.