Geography - Tectonic Hazards

Question 1

Natural Hazard

Answer 1

An event that threatens people or has the potential to cause damage, destruction and death

Question 2

Conservative plate margin

Answer 2

Tectonic plate margin where two tectonic plates slide past each other

Question 3

Constructive plate margin

Answer 3

Tectonic plate margin where rising magma adds new material to plates that are ‘diverging’ or moving apart

Question 4

Destructive plate margin

Answer 4

Tectonic plate margin where two plates are converging or coming together and the oceanic plate is subducted. It can be associated with violent earthquakes and explosive volcanoes

Question 5

Earthquake

Answer 5

A sudden or violent movement within the Earth’s crust followed by a series of shocks

Question 6

Immediate responses

Answer 6

The reactions of people as a disaster happens and in the immediate aftermath

Question 7

Long-term responses

Answer 7

Later reactions that occur in the weeks, months and years after an event

Question 8

Monitoring

Answer 8

Recording physical changes, such as earthquake tremors around a volcano, to help forecast when and where a natural hazard might strike

Question 9

Plate margin

Answer 9

The margin or boundary between two tectonic plates

Question 10

Planning

Answer 10

Actions taken to enable communities to respond to, and recover from, natural disasters, through measures such as emergency evacuation plans, information management etc.

Question 11

Prediction

Answer 11

Attempts to forecast when and where a natural hazard will strike, based on current knowledge. This can be done to some extent for volcanic eruptions, but less reliably for earthquakes

Question 12

Primary effects

Answer 12

The initial impacts of a natural event on people and property, caused directly by it; for instance, buildings collapsing following an earthquake

Question 13

Protection

Answer 13

Actions taken before a hazard strikes to reduce its impact, such as educating people or improving building design

Question 14

Secondary effect

Answer 14

The after-effects that occur, sometimes on a longer timescale, for instance, fires due to ruptured gas mains resulting from the ground shaking

Question 15

Tectonic hazard

Answer 15

A natural hazard caused by movement of tectonic plates

Question 16

Tectonic plates

Answer 16

A rigid segment of the Earth’s crust which can ‘float’ across the heavier, semi-molten rock below. Continental Plates - less dense but thicker than Oceans plates

Question 17

Volcano

Answer 17

An opening in the Earth’s crust from which lava, ash and gases erupt

Question 18

Atmospheric hazards

Answer 18

Created in the atmosphere, by the movement of air and water

Question 19

Examples of atmospheric hazards

Answer 19

Tropical storms, extreme weather (heat waves, cold spells), storm surge

Question 20

Terrestrial/Geological hazards

Answer 20

Created by the movement of the Earth’s tectonic plates or surface rock and soils

Question 21

Examples of Geological hazards

Answer 21

Volcanoes, earthquakes, landslides, avalanches, tsunamis

Question 22

Water based hazards

Answer 22

Created by rivers, sea or oceans

Question 23

Convection Currents

Answer 23

The hot core causes magma to rise in the mantle and sink towards the core when it cools, convection builds pressure and it carries plates with it

Question 24

Slab pull

Answer 24

The denser plate sinks back in the mantle under the influence of gravity, it pulls the rest of the plate along behind it

Question 25

Ridge push

Answer 25

Magma rises as the plates move apart, the magma cools to form a new plate material, as it cools it becomes denser and slides down away from the ridge, this causes tectonic plates to move away from each other

Question 26

Volcanic gases

Answer 26

These are compressed underground but once released into the atmosphere they can change global temperatures. Some gases like CO₂ are fatal in high concentrations when ejected from volcanoes

Question 27

Landslides

Answer 27

This is when a section of the volcano falls down the side of a mountain

Question 28

Lahar

Answer 28

These are a mixture of volcano ash rocks and other debris mixed with either hot or cold water. They can destroy whole towns and many move fast for people to out run

Question 29

Lava Flows

Answer 29

These are eruptions of molten rock from deep within the Earth. Some are slow and sticky others are runny and fast flowing. They can burn down buildings and cause widespread destruction

Question 30

Pyroclastic flows

Answer 30

These are mixtures of hot, dry ash, rock and gas from volcanic eruptions. They travel about 80km per hour and range from 200-700°C

Question 31

Tephra

Answer 31

This is anything that is blown out of the volcano into the air. It can vary in size from tiny ash particles to chunks of rocks the size of cars

Question 32

Jökulhlaup

Answer 32

A glacial outburst, when a glacier that is on top of a volcano melts due to a volcanic eruption