Hazards Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Avalanche

A

A slide of a large snow or rock mass down a mountainside caused when a build up of snow is released.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Landslides

A

Similar to Avalanches except instead of snow, it involves pieces of the earth, such as dirt, trees and rocks. Landslides can be caused by earth quakes, volcanic eruptions and unstable land.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mudflows

A

A special case of landslides in wish heavy rainfall causes loose soil on steep terrain to collapse and slide downwards.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Flood

A

The result of prolonged rainfall that isn’t able to drain from an area fast enough

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Wild fire

A

An uncontrolled fire burning in wildland areas. Can be caused by drought or human negligence.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cyclonic storms

A

Also called hurricane and typhoon. A storm system that forms over oceans. Caused when evaporating water comes off the ocean and becomes a storm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tornado

A

A natural disaster resulting from a thunderstorm. Violent, rotating columns of air which blow at speeds between 50 and 300 mph.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Lahar

A

A large amount of material, including mud, rock and ash sliding down the side of a volcano at a rapid pace during an eruption. Associated with heavy rains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Earthquake

A

The ground shaking or moving sideways. Usually occur along plate boundaries due to two or more plates moving, causing energy to be released.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Tsunami

A

A wave of water caused by the displacement of a body of water. Can be caused by underwater earthquakes, or landslides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Volcanic eruption

A

The point in which a volcano is active and releases its power. Usually occurs along plate boundaries due to plates moving apart, releasing lava from the mantle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Hazard risk

A

The probability that a natural hazard may take place.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Hazard risk

A

The probability that a natural hazard may take place.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Hazard perception

A

The way we react in different ways to hazards, because of the differences in the way we process and filter infomation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Potential factors in hazard response

A

Wealth, Age, Gender, Religion, ecenomic development of nation, hazard magnitude, hazard frequency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Fatalism

A

When people accept the risk and consequences of living in a hazardous area, due the potential reward. Eg fertile soil near volcanoes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Adaption

A

When an area changes their way of living in order to be able to live with hazards.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Prediction

A

Predicting when a hazard takes place in order to reduce the impact. Includes: seismic monitering, measuring gas volcanic gas emissions, satellite observations, geological ground changes and odd animal behaviour before an earthquake.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Mitigation

A

Any action taken to reduce or eliminate the threat to property or human life.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Risk sharing

A

Spreading the risk of a natural hazard resulting in any one group’s / individual’s risk reducing. Can involve spreading financial burden

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Management

A

An umbrella term for any actions taken to reduce the impact of natural hazards. Adaption, prediction, mitigation, and risk sharing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The Park model

A

A model of hazard response considers how the standard of living and economic status of an affected area changes following an event.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Relief phase

A

The immediate response, focusing on saving lives and property. Urgent medical supplies may be brought in.

24
Q

Rehabilitation phase

A

May last several months - efforts are made to restore physical and community structures, at least temporarily.

25
Q

Reconstruction, mitigation, preparing.

A

Permanent changes are introduced to restore the quality of life and economic stability to at least the pre-disaster level (or more). Can also include mitigation and preparing for future hazards.

26
Q

Slab pull

A

At subduction zones gravity ‘pulls’ the oceanic plate down into the mantle. This destroys crust material and keeps the earth in shape.

27
Q

Ridge push

A

The process of material pushing out from the ridge is known as ridge push

28
Q

Lithosphere

A

The solid top layer of crust in which plates are formed. Consists of crust and upper mantle.

29
Q

Asthenosphere

A

Soft, plastic like rock in the uppermantle just below the lithosphere

30
Q

Destructive margin

A

One plate sinks under another (subduction)

31
Q

Constructive margin

A

Two plates move away from each other

32
Q

Conservative

A

Two plates move past each other

33
Q

Collision margin

A

Two continental plates move together

34
Q

Continental crust

A

25-70km thick
Aprox 4 billion years old
Density 2.7 gcm^-3
Consists of oxygen, silicon, aluminium, iron, calcium
Granite, sedimentary and metamorphic rocks

35
Q

Oceanic

A

6-7km think
Aprox 200 million years old
Density 3gcm^-3
Consists of silica and magnesium primaraly
Basalt and gabbro rocks

36
Q

Pieces of evidence for plate tectonics

A
  • Jigsaw fit
  • Tectonic evidence
  • Geological fit
  • Paleomagnetism
  • Fossil evidence
37
Q

Paleomagnetism

A

New material is constantly being produced at the mid ocean ridge and takes the polarity of the earth of when it was made. Earth’s magnetism randomly flips sometimes meaning we can see a striped pattern in the polarity of the rock. This could only be possible due to the sea floor moving due to plates.

38
Q

Jigsaw fit

A

The similarity in the outline of the coastlines of eastern South America and west Africa points to the continents being moved by the movement of plates. Gaps or overlaps can be explained by coastal erosion and deposition.

39
Q

Tectonic fit

A

Fragments of an old fold mountain belt around 425 million years old are found widely spread across multiple continents today

40
Q

Geological fit

A

When the geology of eastern South America and West Africa was mapped it revealed that ancient rock outcrops over 2000 million years old were continuous from one continent to the other

41
Q

Fossil evidence

A

There are many examples of fossils found on separate continents and nowhere else, suggesting the continents were once conjoined

42
Q

Ocean Ridges

A

A line of undersea volcanoes created by tectonic activity.

43
Q

Rift Valleys

A

A lowland region that forms where Earth’s tectonic plates move part

44
Q

Graben

A

Areas that have dropped in a rift valley.

45
Q

Horst

A

Areas that rise in a rift valley.

46
Q

When continental and oceanic crust meet at a destructive boundary

A

Subduction occurs; the thinner and denser oceanic crust sinks below the continental crust into the mantle.
Very seismically active - violent volcanoes and earthquakes
Deep ocean trenches and fold mountains formed

47
Q

When two oceanic crusts meet at a destructive boundary

A

Subduction occurs; one plate is forced under the other, due to it being marginally denser or moving quicker.
Causes earthquakes, some of which can be very powerful.
Ocean trenches and island arcs are formed, for example Marianas trench.

48
Q

When two continental plates meet at a destructive boundary.

A

Continental plates are of lower density than the asthenosphere beneath them therefore subduction does not occur.
The plates instead collide, causing very powerful earthquakes e.g Nepal 2015.
Sediments from vanishing ocean floors are compressed to form fold mountains.

49
Q

The two types of volcanoes

A

Shield Volcanoes
Composite volcanoes

50
Q

Shield Volcanoes

A
  • Gentle slopes and wide base
  • Frequent eruptions of high speed, non-viscous lava that flows for long distances
  • Usually non violent eruptions
  • Found at constructive boundaries
51
Q

Composite volcanoes

A
  • High and steep sided with a narrow base
  • Explosive eruptions of viscous lava and ash that does not flow far from the crater
  • Layers of alternating ash and lava
52
Q

Icelandic volcano

A

Low viscosity and highly effusive.

53
Q

Hawaiian

A

Effusive, minor explosivity, with fire fountain and low viscosity lava flow

54
Q

Strombolian

A

Eruption with gas bubbles so eject tephra

55
Q

Vulcanian

A

Higher gas build up than Strombolian, highly viscous lava. A series of short lived explosions, with tephra including bombs

56
Q

Pelean

A

Explosive eruptions with range of tephra with nuee ardent pyroclastic flows

57
Q

Plinian

A

Highly explosive, large eruption column, range of tephra and pyroclastic fallout, including flows