The challenge of natural hazards: Natural hazards - Keywords

Question 1

Hazard risk

Answer 1

The probability or chance that a natural hazard may take place.

Question 2

Natural hazard

Answer 2

A natural event (for example an earthquake, volcanic eruption, tropical storm, flood) that threatens people or has the potential to cause damage, destruction and death.

Question 3

Earthquake

Answer 3

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

Question 4

Immediate responses

Answer 4

The reaction of people as the disaster happens and in the immediate aftermath.

Question 5

Long-term responses

Answer 5

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

Question 6

Monitoring

Answer 6

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

Question 7

Plate margin

Answer 7

The margin or boundary between two tectonic plates.

Question 8

Planning

Answer 8

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

Question 9

Prediction

Answer 9

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 (and tropical storms), but less reliably for earthquakes.

Question 10

Primary effects

Answer 10

The initial impact of a natural event on people and property, caused directly by it, for instance the ground buildings collapsing following an earthquake.

Question 11

Protection

Answer 11

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

Question 12

Secondary effects

Answer 12

The after-effects that occur as indirect impacts of a natural event, sometimes on a longer timescale, for instance fires due to ruptured gas mains resulting from the ground shaking.

Question 13

Tectonic hazard

Answer 13

A natural hazard caused by movement of tectonic plates (including volcanoes and earthquakes).

Question 14

Tectonic plate

Answer 14

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

Question 15

Volcano

Answer 15

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