Key Terms

Question 1

Asthenosphere

Answer 1

The upper mantle layer of the Earth. It is semi-molten and approximately 2000km wide

Question 2

Ash

Answer 2

Fine particles and dust ejected during an eruption, which can remain airborne as clouds or accumulate on the ground

Question 3

Benioff Zone

Answer 3

A region of the subducting plate, most affected by pressure and friction, where most destructive margin earthquakes origionate

Question 4

Continental Crust

Answer 4

Crust that inhabits 40% of the crust, approximately 35km thick.

Question 5

Continental Drift

Answer 5

The movement of tectonic plates, due to varying weights of crust. It was origionally thought that convection currents caused the movement of the plates, but now slab pull is thought of as the primary driving force.

Question 6

Controlled Burning

Answer 6

Intentionally burning vegetation with the aim of reducing fuel available for a wildfire and disrupting the fire’s path.

Question 7

Convection Currents

Answer 7

The circulation of magma within the asthenosphere. Magma is heated by radioactive processes in the core and cools at the surface , and so circulates between the two plates.

Question 8

Coriolis Effect

Answer 8

The Earth’s spin affects the movement of air masses and winds, depending on a locations latitude.

Question 9

Crown fires

Answer 9

Wildfires that burn the entirety of a tree (from top to bottom), often the most destructive and dangerous type of wildfire.

Question 10

Park Model

Answer 10

This model shows how quality of life is affected by any hazardous event.

Question 11

Epicentre

Answer 11

The point on the surface, directly above the earthquakes focus.

Question 12

Fatalism

Answer 12

The belief that hazards are uncontrollable, so any losses should be accepted and mitigation is unnecessary.

Question 13

Fire Breaks

Answer 13

The felling of trees and clearing vegetation to create a gap to disrupt a wildfire’s path

Question 14

Focus

Answer 14

The place in the crust where the pressure/seismic energy is released

Question 15

Ground Fires

Answer 15

Wildfires that burn through the peat and vegetation beneath the surface, making them slow but difficult to extinguish

Question 16

Hazard Management Cycle

Answer 16

The sequence of governance of a natural hazard: preparedness, response, recovery and mitigaiton

Question 17

Hot Spot

Answer 17

Volcanoes found away from the plate boundary, due to a magma plume closer to the surface

Question 18

Jokulhlaups

Answer 18

Sudden glacial floods caused by a glacier on top of or near a volcano melting due to the heat from eruption.

Question 18

Lahar

Answer 18

A flow of water, mud and debris

Question 18

Lithosphere

Answer 18

The upper crust of the Earth, average thickness of 100km

Question 19

Mid-Ocean Ridge

Answer 19

Parting oceanic plates at a constructive plate boundry creates a ridge, with new land at the base of the oceanic valley

Question 20

Moment Magnitude Scale

Answer 20

A measure of an earthquake’s energy released. Considered the most accurate measure

Question 21

Oceanic Crust

Answer 21

Crust, usually thinner than continental crust, that forms at the sea floor. On average 7km thick

Question 22

Paleomagnetism

Answer 22

The alternating polarisation of new land created. As magma cools, the magnetic elements within will align with the Earth’s magnetic field, which can alernate over thousands of years

Question 23

Park's Model

Answer 23

A model describing the decline and recovery of a country over time, following a natural disaster

Question 24

Primary Waves

Answer 24

An earthquake wave causing compressions within the body of a rock

Question 25

Pyroclastic Flow

Answer 25

A mixture of gases and rock fragments, at high temperatures travelling at rapid speeds

Question 26

Richter Scale

Answer 26

A logarithmic measuire of earthquake's intensity

Question 27

Secondary Waves

Answer 27

An earthquake wave causing vertival displacement within the body of the rock

Question 28

Seismic Waves

Answer 28

The energy released during an earthquake, in the form of Primary, Secondary, Love and Rayleigh waves

Question 29

Slab Pull

Answer 29

The force contributing to the movement of tectonic plates. Slab pull is due to the weight of the plate

Question 30

Subduction

Answer 30

Oceanic plate is forced below continental plate, due to the oceanic plate being more dense than the continental plate

Question 31

Surface Fires

Answer 31

Wildfires that only burn the leaf litter, and so are the easiest kind to extinguish

Question 32

Tropical Storm

Answer 32

A low pressure system of spiralling winds (due to the coiolis effect). Called Hurricanes, Cyclones and Typhoons

Question 33

Tsunami

Answer 33

Initial vertical water displacement (often from a submarine earthquake) creates waves, with large destructive power.

Question 34

Volcanic Explosivity Index (VEI)

Answer 34

A meaure of the magnitude of a volcano's eruptions

Question 35

Volcanic Island Arc

Answer 35

A series of volcanoes (often in the shape of an arc) that are formed consecutively, as a tectonic plate moves across a magma plume

Question 36

Wildfire

Answer 36

A large, uncontrolled fire that quickly spreads through vegetation

Question 37

How wide is the asthenosphere?

Answer 37

Approximately 2000km.