Tectonics Key Words Flashcards

1
Q

What is Ash?

A

The very fine particles of rock ejected during a volcanic eruption- forming part of the tephra

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2
Q

What is Tephra?

A

term for all sizes of ejected volcanic material

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3
Q

What is the Asthenosphere?

A

Top part of the mantle, where rock is semi molten, below the Lithosphere

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4
Q

What is the Lithosphere?

A

The solid part of the mantle and the crust, above the asthenosphere

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5
Q

What is the Benioff zone?

A

Area where friction is created between colliding tectonic plates, creating intermediate and deep earthquakes

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6
Q

What is a Collision plate boundary?

A

When two plates move towards each other, causing slow collision which causes folding and faulting of crystal rocks + uplift of continental crust, forming mountains

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7
Q

What is Community Adaptation?

A

People within communities work together to change their way of life to reduce the impact of tectonic hazards and make the event less hazardous

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8
Q

What is Community Preparedness?

A

People within communities work together to change their way of life to reduce the impact of tectonic hazards and make the event less hazardous

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9
Q

What is a Conservative plate movement?

A

When two plates move alongside each other, either in similar or opposite directions, at different speeds. Friction is high between the plates, stress and strain builds up, creates earthquake foci
At a Transform plate boundary

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10
Q

What is an Earthquake focus?

A

The point in the earth’s crust where an earthquake originates

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11
Q

What is a Constructive plate boundary?

A

When two plates move in opposite directions, leaving a zone of faulting and a gap into which magma from the asthenosphere rises
At a Divergent plate boundary

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12
Q

What are Convection currents?

A

Hot, liquid magma moving into the asthenosphere

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13
Q

What is a Convergent plate boundary?

A

Where 2 plates move towards each other and the denser oceanic plate (basaltic) subducts beneath the less dense continental plate (granitic)
Creates surface features like a trench and deep features like the Benioff Zone
At a Destructive Plate Boundary

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14
Q

What is Crustal Fracturing?

A

When energy released during an earthquake causes the earth’s crust to crack

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15
Q

What is the Epicentre?

A

The point on the earth’s surface directly above the focus of the earthquake

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16
Q

What is the Focal Depth?

A

The depth at which an earthquake starts, divided into shallow, intermediate and deep.

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17
Q

Which depth of earthquake has the greatest impact + why?

A

Shallow earthquakes, seismic waves have not lost much energy by the time they reach the surface

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18
Q

What is the Focus?

A

The point inside the earth’s crust from which pressure is released when an earthquake occurs

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19
Q

What is a Geological structure?

A

The arrangement of rocks in layers, or folds and the joints and bedding planes within them

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20
Q

What is a Hazard Management cycle?

A

A theoretical model of Hazard Management as a continuous 4 stage cycle involving Mitigation, Preparation, Response and Recovery

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21
Q

What is a Hazard Profile?

A

An analysis of different types of hazard, or actual events, based on a range of criteria. Allows for useful comparison to be made

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22
Q

What is a Hot Spot?

A

Points within the middle of a tectonic plate where plumes of hot magma rise and erupt

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23
Q

What are Hydrometeorological Hazards?

A

Natural Hazards caused by climate processes, ie droughts, floods, hurricanes, storms

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24
Q

What are Intraplate Earthquakes?

A

Earthquakes which occur far from plate margins

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25
What are L waves?
The slowest seismic waves, which focuses all the energy on the earth's surface
26
What is a Lahar?
A mixture of meltwater from snow and ice on top of an active volcano that travels very quickly down existing river valleys, reaching some distance away from the volcano
27
What is Land use Zoning?
A process a local government uses to decide how land can be used by a community
28
What is a Landslide?
A mass movement of rock and soil down a steep slope by gravity Can be triggered by an earthquake loosening material
29
What is Lava
Molten magma that reaches the earth's surface
30
What is Lava flow?
Molten magma that reaches the earth's surface that flows down the side of a volcano and solidifies
31
Which lava flow is faster and why?
Basaltic lavas flow faster than andesitic lavas because of different velocities
31
What are Seismic hazards?
Generated when rocks within 700km of the Earth's surface come under such stress that they buckle and displace
32
What is Liquefaction?
When violent shaking during an earthquake causes surface rocks to lose strength and become more liquid than solid
33
What is the Lithosphere?
The solid layer that forms tectonic plates, made up of the upper mantle and crust
34
What is Magnitude?
The amount of energy releases by a tectonic event
35
What are the Earthquake and Volcano Magnitude scales?
Earthquake scale= Moment Magnitude Scale (MMS) Volcano scale= Volcano Explosivity Index (VEI)
36
What is Mass Movement?
The downward movement of material under the influence of gravity, ie rockfalls, landslides, solifluction
37
What is a Mega Disaster?
When a major hazardous event becomes catastrophic and more than a disaster ie scale of impacts (deaths, loss of infrastructure) are severe or long lasting socio-economic impacts
38
What is the Mercali Scale?
An earthquake intensity scale based on 12 levels of damage to areas
39
What is Mitigation?
Action to reduce the impacts of an event
40
What is Modify loss?
Reduce the impact of loss from a tectonic hazard ie insuring belongings and property
41
What does Modify the event mean?
Alter the natural hazards themselves to change the likely impacts Earthquakes cannot be changed, but some volcanic activity can be modified, ie by diverting lava flow
42
What does Modify Vulnerability mean?
Vulnerability is key in identifying the impact of a hazard Making people less vulnerable will reduce the scale of the disaster
43
What is the Moment Magnitude Scale (MMS)?
The most accurate earthquake magnitude scale- measures the total energy released by an earthquake
44
What is a Multiple Hazard Zone?
An area that is at risk from multiple natural hazards like Hurricanes and Earthquakes
45
What is a Natural Hazard?
A physical geographical event (tectonic, hydrological or meteorological) which has a negative impact on people through causing injury or death, loss of property or disruption to everyday life
46
What are P waves?
The fastest seismic waves which travel through both solids and liquids
47
What is Paleomagnetism?
The study of past magnetic changes in the Earth's magnetic field
48
What is the Park Model?
Shows how a country or region might respond after a hazard event
49
What is a Pressure and Release model (PAR)?
A tool used to work out how vulnerable a country is to hazards
50
What is Rapid onset?
A hazard that happens with little to no warning very quickly ie a Hurricane
51
What is Resilience?
The ability of a community to resist the impacts of a hazard by adapting and recovering
52
What are S waves?
Seismic waves which only travel through solids and move in a sideways motion
53
What is Sea Floor Spreading?
The movement of oceanic crust away from a constructive plate boundary, as recorded in the magnetic strips in basaltic rock (palaeomagnetism)
54
What is Slab Pull?
When newly formed oceanic crust sinks into the mantle, pulling the rest of the plate down with it
55
What is Slow Onset?
A hazard that happens very slowly with plenty of evidence and warning, such as a drought
56
What are Sub aerial processes?
The processes of weathering and mass movement
57
What is the Subduction zone?
The area in the mantle where a tectonic plate meets
58
What is a Transform fault?
A fault created on a large scale where 2 plates slide past each other
59
What is the Volcanic Explosivity Index (VEI)?
The scale used to measure the magnitude of a volcanic eruption
60
What is water column displacement?
The movement of a volume of seawater above the point at which the seabed was moved up or down by an earthquake, such as a thrust
61
What are the different types of plate boundaries?
Convergent/Destructive Divergent/Constructive Transform/Conservative
62
What is an Ocean trench?
A long, narrow depression on the sea floor due to a collision boundary
63
What is an Island arc?
Destructive boundary away from a continental area
64
What are intra-plate earthquakes?
Occur in the middle or interior of tectonic plates, rarer than boundary earthquakes
65
What is a Volcano?
A landform that develops around a weakness in the Earth's crust from which molten magma, volcanic rock + gases are ejected or extruded
66
What is the Lithosphere?
The surface layer of the Earth is a rigid outer shell composed of the crust and upper mantle, around 100km deep. The lithosphere is always moving, fuelled by the rising heat from the mantle causing convection currents. The lithosphere is broken into huge sections, which are tectonic plates.
67
What is Plate Tectonics?
A theory that developed more than 60 years ago to explain the large-scale movement of the lithosphere Based on evidence of seafloor spreading and paleomagnetism