Tectonic Keywords

Question 1

Ash falls

Answer 1

Small particles of rock and volcanic glass that land after a volcanic eruption has blasted them into the air

Question 2

Asthenosphere

Answer 2

The part of the mantle, below the lithosphere, where the rock is semi molten

Question 3

Benioff zone

Answer 3

The area where friction is created between colliding tectonic plates, resulting in intermediate and deep earthquakes

Question 4

Body waves

Answer 4

The group name for primary and secondary seismic waves, because they travel through the earths body

Question 5

Collision margin

Answer 5

Where two continental plates meet and the sediments between them are crumpled and forced up to form high fold mountains

Question 6

Conservative plate margin

Answer 6

Where two plates slide past each other also known as a transform margin

Question 7

Constructive margin

Answer 7

Where two plates move apart, also known as a divergent boundary

Question 8

Continental crust

Answer 8

Older, thicker layer of crust, which makes up the earths landmasses. It is less dense than oceanic crust

Question 9

Convection currents

Answer 9

Hot, liquid magma currents moving in the asthenosphere

Question 10

Convergent boundary

Answer 10

Where two plates move towards each other and collide, also know as a destructive margin

Question 11

Crustal fracturing

Answer 11

When energy released during an earthquake causes the earths crust to crack

Question 12

Deep ocean trench

Answer 12

A deep ditch in the ocean, marking the place where an oceanic plate starts to sink beneath a continental plate

Question 13

Destructive margin

Answer 13

Where two plates move towards each other and collide, also known as a convergent boundary

Question 14

Divergent boundary

Answer 14

Where two plates move apart, also known as a constructive margin

Question 15

Epicentre

Answer 15

The point on the earths surface directly above the focus

Question 16

Focus

Answer 16

The point inside the earths crust from which the pressure is released when an earthquake occurs

Question 17

Fold mountains

Answer 17

Chains of mountains, formed when two plates collide and the continental plate is folded and slowly pushed up

Question 18

Gas eruptions

Answer 18

When volcanic gases (water vapour, carbon dioxide and sulphur dioxide) that were dissolved in the magma are released into the atmosphere during an eruption

Question 19

Hazard adaptation

Answer 19

Strategies designed to reduce the impacts of hazard events

Question 20

Hazard mitigation

Answer 20

Strategies meant to avoid, delay or prevent hazard events

Question 21

Hazard management cycle

Answer 21

a theoretical model of hazard management as a continuous 4-stage cycle involving mitigation, preparation, response and recovery

Question 22

Hot spot

Answer 22

an area where radioactive decay within the Earth’s core is concentrated, generating very hot temperatures and heating the lower mantle. This creates localised thermal currents where magma plumes rise

Question 23

hydrometeorological hazards

Answer 23

natural hazards caused by climate processes (including droughts, floods, hurricanes and storms)

Question 24

Intra plate earthquakes

Answer 24

Earthquakes which occur far from the plate margins

Question 25

Island arcs

Answer 25

curved lines of islands, formed when underwater volcanoes grow and rise above sea level to form separate island volcanoes

Question 26

jökulhlaups

Answer 26

A heavy and sudden flood caused when the heat of a volcanic eruption melts the snow and ice in a glacier

Question 27

L waves (surface Love waves)

Answer 27

Seismic waves which travel on the surface and are the slowest waves but cause the most damage

Question 28

Lahars

Answer 28

Masses of rock, mud and water that travels quickly down the sides of a volcano

Question 29

Land use zoning

Answer 29

A process by which local government regulates how land in a community may be used

Question 30

Landslides

Answer 30

when blocks of rock moves very rapidly downhill, caused when the ground shaking during an earthquake places stress on the slopes

Question 31

Lava flows

Answer 31

streams of lava that have erupted from a volcano onto the Earth’s surface

Question 32

Liquefaction

Answer 32

when the violent shaking during an earthquake causes surface rocks to lose strength and become more liquid than solid

Question 33

Lithosphere

Answer 33

the solid layer, made from the crust and upper mantle, from which tectonic plates are formed

Question 34

Magma plume

Answer 34

a rising column of hot rock created by hot spots heating the lower mantle, creating localised thermal currents

Question 35

Mid ocean ridges

Answer 35

underwater mountain ranges, formed when hot magma is forced up from the asthenosphere and hardens, creating new oceanic crust

Question 36

Modified Mercalli Intensity Scale

Answer 36

takes observations from people who experienced the earthquake and rates them on a scale from I (hardly noticed) to XII (catastrophic)

Question 37

Moment magnitude scale

Answer 37

measures the total energy released by an earthquake at the moment it occurs

Question 38

Multiple hazard zone

Answer 38

an area that is at risk from multiple natural hazards such as hurricanes and earthquakes

Question 39

Natural disaster

Answer 39

a major natural hazard that causes significant social, environmental and economic damage

Question 40

Natural hazard

Answer 40

a naturally occurring process or event that has the potential to affect people

Question 41

Non governmental organisation

Answer 41

a non-profit organisation created by private organisations or people with no participation or representation by any government

Question 42

Oceanic crust

Answer 42

a thin, dense layer of crust, which lines the ocean floors

Question 43

P waves (Primary or pressure waves)

Answer 43

the fastest seismic waves and the ones which reach the surface first. They are high-frequency and pushing like balls in a line. They travel through both the mantle and core

Question 44

palaeomagnetism

Answer 44

the study of past changes in the Earth’s magnetic field

Question 45

Pressure and release model

Answer 45

a tool used to work out how vulnerable a country is to hazards

Question 46

Pyroclastic flows

Answer 46

a mixture of dense hot rock, lava, ash and gases ejected from a volcano, which move very quickly across the Earth’s surface

Question 47

Rift valleys

Answer 47

steep-sided valleys, formed at divergent boundaries when the crust stretches and the land between parallel faults collapses

Question 48

S waves (Secondary or shear waves)

Answer 48

seismic waves which are slower than P waves and only travel through solids, with a sideways motion. They do more damage than P waves

Question 49

Sea floor spreading

Answer 49

when new oceanic crust – formed when hot magma is forced up from the asthenosphere and hardens – pushes the tectonic plates apart

Question 50

Slab pull

Answer 50

when newly formed oceanic crust sinks into the mantle, pulling the rest of the plate further down with it

Question 51

Subduction

Answer 51

when two plates move towards each other and one slides under the other into the mantle

Question 52

Subduction zone

Answer 52

the area in the mantle where a tectonic plate melts

Question 53

the Park model (hazard- response curve)

Answer 53

shows how a country or region might respond after a hazard event

Question 54

Transform fault

Answer 54

A fault created on a large scale when two plates slide past each other

Question 55

Transform margin

Answer 55

Where two plates slide past each other, also known as a conservative boundary

Question 56

Tsunami

Answer 56

A series of larger than normal waves which are usually caused by volcanic eruptions or underwater earthquakes

Question 57

Urbanisation

Answer 57

The increasing proportion of people living in towns and cities as opposed to the countryside

Question 58

Volcanic Explosivity Index (VEI)

Answer 58

A logarithmic scale between 0 and 8 which is used to describe and compare the size or magnitude of volcanic eruptions

Question 59

Water column

Answer 59

Water that is displaced above the sea floor when an earthquake has caused the sea floor to uplift. This water column will form tsunami waves