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Flashcards in theme two Deck (218)
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1

volcano def

cone shaped mountained formed by eruptions of lava at the surface of the earth

2

crater def

a depression on the surface of a volcano, formed by volcanic activity, often circular in shape with deep sides.

3

vent def

the natural pipe or fissure that links the magma chamber to the crater or opening on the earths surface through which lava, ash and gases flow.

4

lava def

magma that has escaped from beneath the earth's crust and has flowed onto the surface.

5

tectonic plates def

huge pieces of the earths crust that float and move on top of the much denser mantle below them

6

constructive/divergent plate boundary def

where two plates move apart, allowing magma to come to the surface as lava

7

magma def

molten rock found beneath the earths crust

8

magma chamber def

a large natural underground chamber of magma found within the surface of the earth beneath a volcano.

9

destructive/convergent plate boundary def

where two plates move towards each other

10

subduction def

when one plate sinks below another

11

hot spot def

a central part of the earths crust where plumes of magma rise to the earths surface

12

how can magma leave a volcano on to the earths crust

lava
volcanic bombs
very fine ash

13

what can volcanic eruptions be accompanied by

pyroclastic flows
lahars
earthquakes

14

composite/strato volcanoes

these are made from alternating layers of lava and ash as both come out of the vent during an eruption.

15

where do composite/strato volcanoes form

on destructive plate boundaries

16

shield volcanoes

these are made from lava. they from large volcanoes with gently sloping sides, sometimes hundreds of kilometres across before cooling and solidfying

17

where do shield volcanoes form

on a constructive plate boundary

18

dome volcanoes

these are also made from lava but the lava is acid and thicker and cools quicker. it does not flow very far before becoming solid and are steep sided and high.

19

active volcano

one that has recently erupted and is likely to again.

20

domant volcano

one that has erupted in the last 2000 years and may erupt again. hard to predict.

21

extinct volcano

long since finished erupting and has cooled down

22

earthquake def

a sudden and often violent shift in the rocks forming the earth's crust, which is felt at the surface.

23

fault line def

a fracture or break in the earths surface along which rocks have moved alongside each other

24

focus def

the location of the actual source of an earthquake below the ground surface; also called the origin

25

conservative platae boundary def

where two plates are sliding alongside each other

26

epicentre def

location on the surface of the earth above the focus or origin of the earthquake

27

tsunami def

powerful, devastating waves at the coast caused by an undersea earthquake or volcanic eruption that displaces the water lying above it

28

seismometer def

an instrument that meaures movement of the ground, including the seismic waves generated by earthquakes and volcanic eruptions

29

seismic waves

waves of energy that travel through the earths layers as a result of earthquakes, volcanic eruptions, magma movements and large landslides

30

moment magnitude scale and richter scale def

numerical scales showing the size or magnitude of an earthwuake based on readings from a seisometer