Tectonics

Question 1

Accretion Wedge​

Answer 1

The accumulation of material at the point of subduction.

Question 2

Aseismic Buildings

Answer 2

Buildings designed to withstand or minimise destruction during an
earthquake.

Question 3

Asthenosphere

Answer 3

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

Question 4

Ash​

Answer 4

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

Question 5

Continental Crust​

Answer 5

Crust that forms the continents of the lithosphere, on average 35km thick.

Question 6

Continental Drift​

Answer 6

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

Question 7

Convection Currents​

Answer 7

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

Question 8

Degg’s Model​

Answer 8

This model shows that a hazard becomes a disaster if it affects a vulnerable population.

Question 9

Epicentre​

Answer 9

The point on the surface, directly above the earthquake’s origin.

Question 10

Focus

Answer 10

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

Question 11

Hazard Mitigation Cycle

Answer 11

The sequence of governance of a natural hazard: monitoring & prediction, mitigation, preparedness.

Question 12

Hot Spot​

Answer 12

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

Question 13

Jokulhaup

Answer 13

A sudden glacial flood caused by a glacier on top of or near a volcano melting due to the heat from the eruption.

Question 14

Lahar

Answer 14

A flow of mud and debris.

Question 15

Lithosphere​

Answer 15

The upper crust of the Earth (average thickness = 100km).

Question 16

Love Waves​

Answer 16

A surface earthquake wave with horizontal displacement.

Question 17

Mid-Ocean Ridge

Answer 17

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

Question 18

Moment Magnitude Scale

Answer 18

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

Question 19

Oceanic Crust​

Answer 19

Crust, usually thinner than continental crust, that forms the sea floor. It is on average 7km thick.

Question 20

Paleomagnetism​

Answer 20

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

Question 21

Park’s Model​

Answer 21

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

Question 22

Partial Melting​

Answer 22

Elements within the lithosphere have different melting points, and so rock is partially melted, partially solid

Question 23

Primary Waves

Answer 23

An earthquake wave causing compressions within the body of rock.

Question 24

Pyroclastic Flow

Answer 24

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

Question 25

Rayleigh Waves

Answer 25

A surface earthquake wave causing both horizontal and vertical displacement.

Question 26

Richter Scale​

Answer 26

A logarithmic measure of earthquake’s intensity.

Question 27

Secondary Waves​

Answer 27

An earthquake wave causing vertical displacement within the body of 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

Tsunami​

Answer 31

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

Question 32

Volcanic Explosivity Index (VEI)

Answer 32

A measure of the magnitude of a volcano’s eruptions

Question 33

Volcanic Island Arc

Answer 33

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 34

Wadati-Benioff Zone​

Answer 34

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