Hazards key terms

Question 1

geophysical hazard

Answer 1

A natural event that may cause a loss of life and damage to building or land.

Question 2

atmospheric hazard

Answer 2

potentially damaging natural event associated with changes in atmospheric conditions

Question 3

hydrological hazards

Answer 3

extreme events associated with water occurrence, movement, and distribution

Question 4

hazard perception

Answer 4

the way in which an individual or a group view the threat of a hazard event and this then influences their actions

Question 5

fatalism

Answer 5

a view that suggests people cannot influence outcomes therefore nothing can be done to reduce (mitigate) the event or its impacts : an act of God ; people remain

Question 6

prediction

Answer 6

the ability to give warnings so that action can be taken to reduce impacts - improved by monitoring, information sharing and communications technologies

Question 7

adaptation

Answer 7

attempts by individuals and communities to live with hazard events and reduce their level of vulnerability

Question 8

mitigation

Answer 8

actions taken to help reduce or eliminate long-term risks caused by hazards

Question 9

resilience

Answer 9

the sustained ability to respond to, withstand and recover from the effects of natural hazards

Question 10

preparedness

Answer 10

prearranged measures to reduce the loss of life and property damage through education, evacuation procedures, provision of emergency shelters and the taking out of insurance

Question 11

hazard frequency

Answer 11

how often a hazard occurs - generally smaller
hazards occur more frequently, and larger hazards occur less frequently

Question 12

hazard intensity

Answer 12

The measurement of the impacts of the hazard on a place ( e.g. Mercalli scale )

Question 13

magnitude

Answer 13

an assessment of the size of an event (the amount of energy released)

Question 14

hazard distribution

Answer 14

the pattern of where each hazard type is most likely to occur (and areas which don’t experience these)

Question 15

level of development

Answer 15

is related to increase in economic output (wealth) coupled with improvement in social and political welfare of people within a country

Question 16

Park’s model
(disaster-response curve)

Answer 16

a model graph to show the effects of a hazard on quality of life over a sequence of time and expected stages from pre-event to eventual recovery

Question 17

hazard management cycle

Answer 17

the continuous process by which individuals and communities manage hazards in an effort to avoid or mitigate the impacts resulting from the hazards and learn to manage and prepare for them better over time

Question 18

plate tectonic theory

Answer 18

the theory that Earth’s outer layer is divided into several plates that move over the mantle; the rocky inner layer above the core

Question 19

crustal evolution

Answer 19

the rate of continental crustal growth and recycling through time and how changes in tectonic movement have influenced the rates of crustal growth and preservation

Question 20

tectonic plates

Answer 20

the large, separately moving areas of the lithosphere that are the result of its breaking apart into seven or eight major sections (depending on how they are defined) and many minor ones

Question 21

gravitational sliding

Answer 21

the movement downward or downslope of rock / lava in response to gravitational instability along particular slopes in unstable regions such as mid-oceanic ridges

Question 22

ridge push

Answer 22

a proposed driving force for plate motion that occurs at mid-ocean ridges as the result of the rigid lithosphere sliding down the hot, raised asthenosphere underneath mid-ocean ridges - this push is caused by gravitational force and it exists because the ridge occurs at a higher elevation than the rest of the ocean floor

Question 23

slab pull

Answer 23

the portion of motion of a tectonic plate that can be accounted for by its subduction and it is partly driven by the weight of cold, dense plates sinking into the mantle at oceanic trenches - the cooler sinking plate pulls the rest of the warmer plate along behind it

Question 24

convection currents

Answer 24

heat from the earth’s core is transferred to the mantle. Rock, close to the core, is heated and so has plasticity and so it rises. When it reaches the crust it is forced sideways as often it cannot pass through the crust. The frictional drag between the convection current and the lower surface of the crust causes the tectonic plate to move. The more liquid rock then sinks back towards the core as it cools. The process then repeats.

Question 25

sea-floor spreading

Answer 25

the formation of fresh areas of oceanic crust which occurs through the upwelling of magma at mid-ocean ridges and its subsequent outward movement on either side

Question 26

constructive plate margin

Answer 26

sometimes called a divergent plate margin, occurs when plates move apart and magma wells up to fill the gap forming volcanic activity and new crust

Question 27

destructive plate margin

Answer 27

sometimes called a convergent or tensional plate margin and this occurs when oceanic and continental plates move together leading to folding or subduction

Question 28

conservative plate margin

Answer 28

sometimes called transform faults and these occur when plates slide past each other in opposite directions, but without creating or destroying lithosphere

Question 29

young fold mountains

Answer 29

mountains that form mainly by the effects of folding on layers within the upper part of the Earth’s crust eg the Himalayas - at convergent margins

Question 30

rift valleys

Answer 30

a steep-sided valley formed by the downward displacement of a block of the earth’s surface between nearly parallel faults or fault systems

Question 31

ocean ridges

Answer 31

an elevated region with a central valley on an ocean floor at the boundary between two diverging tectonic plates where new crust forms from upwelling magma.

Question 32

island arcs

Answer 32

volcanic islands that form parallel to ocean trenches in subduction zones

Question 33

Magma plumes

Answer 33

is an upwelling of abnormally hot rock within the Earth’s mantle which can partly melt when they reach shallow depths near the surface and so are thought to be the cause of volcanic centers and hotspots

Question 34

Lava flow

Answer 34

Mass movement on the surface of land of flowing lava

Question 35

Pyroclastic flows

Answer 35

Tephra and hot gases mixed to create a mixture that flows down a volcano

Question 36

Tephra

Answer 36

A solid matter ejected by volcanoes

Question 37

Lahars

Answer 37

Hot mud flows when ash mix’s with water

Question 38

Acid rain

Answer 38

Rainfall that has chemical within it

Question 39

Seismic

Answer 39

Activity related to the earth plates

Question 40

Liquefaction

Answer 40

The decomposition of soil with high water content to bring the water to rise

Question 41

Tsunamis

Answer 41

A giant sea wave created by a large displacement of water

Question 42

Land slide

Answer 42

Mass movement of land downhill

Question 43

Shockwaves

Answer 43

Energy waves produced by an earthquake

Question 44

Storm surges

Answer 44

Large sea waves that occur after a tropical storm due to higher sea levels

Question 45

SaffirSimpson scale

Answer 45

The scale used to measure tropical storm magnitude

Question 46

Retrofitting

Answer 46

Making older building out of new material to be stronger and more resistant

Question 47

Ignition source

Answer 47

a natural or human source of a wildfire being set alight eg lightening or agricultural fires becoming out of control

Question 48

Pyrophitic vegetation

Answer 48

plants adapted to tolerate fire through methods such as thick bark, tissue with high moisture content, seeds set by fire and underground nutrition storage

Question 49

Retardants

Answer 49

chemicals sprayed on wildfires in order to slow them down and made from nitrates, ammonia, phosphates, sulphates and thickening agents

Question 50

Multi-hazardous environment

Answer 50

a place with more than one hazard type happening over time - meaning there are interrelations between these hazards, including their simultaneous (at the same time) or cumulative (one after the other) occurrence and also their potential interactions eg storms + volcanic activity = lahars