Tectonic Processes and Hazards Flashcards Preview

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Flashcards in Tectonic Processes and Hazards Deck (52)
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1

Asthenosphere

The partially molten part of the mantle on which Earth's tectonic plates lie

2

Benioff Zone

The zone where the descending oceanic plate is in contact with the contact with the continental plate as it is subducted. It is a zone of earthquake activity created by friction between the two plates

3

Convection

The movement of mantle material in cells when heated by radiation from the Earth's core

4

Crustal fracturing

Occurs when the earth's crust causes rock to break and fracture under stress and strain caused by seismic stresses

5

Hotspot

An intra-plate location where magma from the mantle has broken through a weak spot in the crust

6

Intra- plate earthquake

Earthquakes that occur away from the plate boundaries and closer to the middle of the tectonic plate

7

Liquefaction

Groundwater or loose soil and sediments are shaken during an earthquake so that the ground loses cohesion and acts like a fluid

8

Lithosphere

The rigid, outermost layer of the earth from which tectonic plated are formed. It is made up of the crust and upper mantle

9

Magnitude

The amount of energy released by a tectonic event

10

Mantle plume

Hotter areas of the mantle that move upwards underneath the crust and push it up. They can cause weak spots in the crust that can become hotspots.

11

Mercalli scale

An earthquake intensity scale based on 12 levels of damage to areas

12

Moment magnitude scale

The most accurate magnitude scale, it measures the total energy released by an earthquake

13

Palaeomagnetism

When magma and lava solidify, the iron materials in the rock align with the Earth's magnetic field, permanently recording the direction

14

Sea floor spreading

The movement of oceanic crust away from a constructive plate boundary, as a recorded by the magnetic stripes in the basaltic rock

15

Seismic waves

The shockwaves created by the release of tension at the focus

16

Slab pull

At a subduction zone the descending part of the oceanic
plate pulls the rest of the plate with it

17

Subduction

The melting of the oceanic plate as it descends into the mantle at a convergent boundary

18

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 event, such as a thrust

19

Volcanoes

Vents in the Earth’s crust through which lava, ash and gases erupt

20

Earthquakes

Vibrations in the Earth’s crust caused by the sudden release of stored energy

21

Plate boundaries

Form where two tectonic plates meet. Plate boundary type depends on plate motion (the direction the pates are moving) and plate type (oceanic or continental crust)

22

Tsunami

A wave or series of waves caused by a disturbance on the sea floor

23

Seismic wave

Waves of energy that travel through the Earth's layers, and are a result of earthquakes, volcanic eruptions and large landslides

24

Primary effect

Occur as direct impact of the tectonic hazard eg. ground shaking

25

Secondary effect

Occur as the result of a primary effect

26

Core

The centre of Earth that is very hot and emits radioactivity due to the isotopes present

27

Mantle

It is made up of magma (semi-molten rock), which the core heats up and creates convection currents, causing the plates to move

28

Tectonic plates

A massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere

29

Hazard risk equation

A tool used to measure risk by taking in account the hazard, the vulnerability and the capacity to cope of the country/location

30

Vulnerability

The risk of exposure to hazards combined with the inability to cope with them