Key Terms

Question 1

Socio-economic disruption:

Answer 1

Disruption to social (lifestyle) or economic (money or jobs) aspects of society.

Question 2

Environmental degradation:

Answer 2

The deterioration of the natural environment.

Question 3

Effusive eruption:

Answer 3

An eruption where lava flows on the ground rather than being expelled in an explosive manner.

Question 4

Basaltic eruption:

Answer 4

A gentle (effusive) eruption, which is characterised by fluid lava and is relatively predictable.

Question 5

Stratovolcano:

Answer 5

A steep-sided volcano made of alternate layers of lava and ash.

Question 6

Hazard perception:

Answer 6

The way in which someone understands or interprets a hazard.

Question 7

Prevention:

Answer 7

The action of stopping something from happening.

Question 8

Prediction:

Answer 8

Suggesting what might happen in the future.

Question 9

Park response model:

Answer 9

A model to show the changing quality of life through different phases of a disaster.

Question 10

Hazard Management Cycle:

Answer 10

A cycle showing phases of response, recovery, mitigation and preparedness in the management of a hazard.

Question 11

Primary hazard:

Answer 11

Hazards that are directly related to the volcano and it’s eruption (eg lava flows, ash falls and gas clouds).

Question 12

Pyroclastic flow:

Answer 12

A mixture of hot rock, lava, ash and gases arising from a volcanic eruption and moves at a rapid speed along the ground.

Question 13

Tephra:

Answer 13

Rock fragments ejected during volcanic eruptions.

Question 14

Nuée ardente:

Answer 14

A dense, rapidly moving cloud of hot gases, ashes and lava fragments from a volcanic eruption; a type of pyroclastic flow.

Question 15

Secondary hazard:

Answer 15

Hazards that occur due to the occurrence of another, primary hazard; they are indirectly related to the volcanic event and, by definition, tend to occur after primary hazards.

Question 16

Lahar:

Answer 16

A destructive mudflow which occurs as a result of a volcanic eruption.

Question 17

Tsunami:

Answer 17

A large wave triggered by seismic activity.

Question 18

Acid rain:

Answer 18

Volcanoes erupt sulphurous gases which can result in acidic rainwater.

Question 19

Intraplate:

Answer 19

In the middle of a plate, away from the plate margins.

Question 20

Subduction zones:

Answer 20

Zones where thin, dense oceanic crust is forced beneath thicker, less dense continental crust at a destructive plate boundary.

Question 21

Shield volcano:

Answer 21

A volcano with gentle sloping sides, charcteristic of fluid, basaltic lava.

Question 22

Caldera:

Answer 22

A large volcanic crater, often formed following a highly explosive eruption where the summit of the volcano is removed.

Question 23

Hotspots:

Answer 23

Sites where mantle plumes rise up through areas of thin crust, causing volcanic activity in areas away from plate boundaries.

Question 24

Magma plume:

Answer 24

An area under the crust, where magma is hotter than surrounding magma. Heat from this extra hot magma causes melting and thinning of the rocky crust, which leads to volcanic activity on Earth’s surface above the plume.

Question 25

Ground deformation:

Answer 25

The change in shape of the ground before or after a volcanic eruption; often it is due to the movement of magma below the surface.

Question 26

Preparedness:

Answer 26

The state of readiness for a volcanic eruption.

Question 27

Mitigation:

Answer 27

The action of reducing the severity or seriousness of a volcanic eruption.

Question 28

Adaptation:

Answer 28

The action of changing or adapting behaviour in order to reduce the severity of a volcanic eruption.

Question 29

Phreatic:

Answer 29

Steam-driven explosions which occur when water beneath the ground is superheated by magma.

Question 30

Volcanic Explosively Index (VEI):

Answer 30

An index that measures the explosively of volcanic eruptions; volcanoes with VEI of 0-1 are effusive, while Plinian eruptions tend to have a VEI of between 4 and 6; there have been 42 eruptions of VEI 8 or above in the last 36 million years, including the eruption of Yellowstone in 640 000 BCE.

Question 31

Plinian eruptions:

Answer 31

Extremely explosive eruptions, producing ash columns that extend many tens of miles into the stratosphere and then spread out into an umbrella shape. Produce widespread deposits of fallout ash.

Question 32

Continental crust:

Answer 32

The Earth’s crust which is found under the continents (although the fit is not exact); it is relatively think (10-70km) and not as dense as oceanic crust.

Question 33

Benioff zone:

Answer 33

The zone where earthquakes tend to occur as the oceanic crust is being subducted underneath the continental crust at a destructive plate boundary.

Question 34

Oceanic crust:

Answer 34

The crust which is found under the oceans (although the fit is not exact); it is relatively thin (5-7km) and more dense than continental crust.

Question 35

Seismometer:

Answer 35

An instrument that measures the seismic waves generated by an earthquake.

Question 36

Unconsolidated sediment:

Answer 36

Loosely arranged particles of sediment that are not joined together.

Question 37

Non-governmental organisation (NGO):

Answer 37

An organisation that is not part of a government or for-profit business; charities such as Oxfam, are good examples of NGOs.

Question 38

Coriolis force:

Answer 38

The rotation of the Earth which deflects objects and air (usually to the right in the northern hemisphere) moving along the Earth’s surface.

Question 39

Latent heat:

Answer 39

The heat required to turn a solid into a liquid or liquid into gas without a change in temperature.

Question 40

Silting:

Answer 40

Where grains of sand or silt accumulate.

Question 41

Convection column:

Answer 41

A vertical, riding column of smoke, ashes and particulates caused by fire.

Question 42

Disaster hotspot:

Answer 42

A location which is at risk of experiencing two or more hazards; Haiti is a good example of a disaster hotspot as it is vulnerable to both tropical storms and earthquakes.

Question 43

Human Development Index (HDI):

Answer 43

A composite index combining life expectancy at birth, mean and expected years of schooling and gross national income (GNI) per capita (calculated at purchasing power parity or PPP US$) to measure and rank countries.

Question 44

Denuded mountains:

Answer 44

Mountains that have been stripped of their vegetation cover.

Question 45

Crowdsourcing:

Answer 45

A way of obtaining information by enlisting the services of a number of people usually through the internet or mobile-phone technology.