hazardous earth - tectonic plates

Question 1

define lithosphere

Answer 1

the upper most layer of the earth - the top of the mantle and the crust

Question 2

define asthenosphere

Answer 2

lower part of the earth’s mantle

Question 3

how hot is the inner core

Answer 3

6000°C

Question 4

how hot is the outer core

Answer 4

5000°C

Question 5

how hot is the mantle

Answer 5

3800°C

Question 6

how thick is the oceanic crust (km)

Answer 6

6-8 km

Question 7

what is the oceanic crust made of

Answer 7

basalt

Question 8

how thick is the continental crust (km)

Answer 8

30-50 km

Question 9

what is the continental crust made of

Answer 9

granite

Question 10

is the oceanic or continental crust denser

Answer 10

the oceanic crust is denser

Question 11

which type of crust can be destroyed (continental or oceanic)

Answer 11

oceanic can be destroyed when two techtonic plates meet

Question 12

what makes the core so hot

Answer 12

radioactive decay of some elements eg
uranium

Question 13

what is the magnetosphere

Answer 13

a huge invisible magnetic field that surrounds the earth, protecting us from harmful radiation from space

Question 14

what part of the earth produces the earth’s magnetic field

Answer 14

the outer core

Question 15

what is pangea and how long ago did it exist

Answer 15

250 million years ago, the continents were once all joined together as one large supercontinent

Question 16

give two points as to how we know that pangea existed

Answer 16

• there are the same fossils in different continents
• some continents appear to fit together

Question 17

define plate boundary

Answer 17

where two plates meet

Question 18

conservative plates - direction
- features/ hazards

Answer 18

• alongside each other or against each other
• destructive earthquakes up to 8.5. small earth tremors almost daily

Question 19

divergent - direction
- features/ hazards

Answer 19

• away from each other
• small earthquakes 5-6 magnitude. not very dangerous volcanoes

Question 20

convergent - direction
- features/ hazards

Answer 20

• towards eachother
• very destructive earthquakes up to 9.5. very destructive volcanoes. tsunamis can form

Question 21

collision - direction
- features/ hazards

Answer 21

• toward eachother
• destructive earthquakes 9. landslides. volcanoes are very rare

Question 22

what are destructive plate boundaries

Answer 22

it’s another name for convergent plate boundaries

Question 23

compare a convergent and collision plate boundary (4)

Answer 23

• both go in the same direction (towards each other)
• both produce extremely destructive earthquakes
• convergent have 1 continental and 1 oceanic but collision have 2 continental
• only convergent can form tsunamis

Question 24

define hotspot and give an example of one

Answer 24

where a rising plume of magma breaks through the earth’s surface in the middle of a plate. this causes a volcano. eh hawaiii

Question 25

define volcano

Answer 25

an opening or vent in the earth's surface through which molten material erupts and solidifies as lava

Question 26

where are composite volcanoes found

Answer 26

convergent boundaries

Question 27

what are composite volcanoes made of and what is the lava Iike

Answer 27

alternating layers of ash and lava andesitic, thick, sticky lava which doesn't flow very far before solidifying

Question 28

what are eruptions like for composite volcanoes and why

Answer 28

they are explosive due to more silica and more gases

Question 29

what are pyroclastic flows and what kind of volcano are they caused by

Answer 29

fast moving current of hot gas and volcanic matter. found at composite volcanoes

Question 30

where are shield volcanoes found

Answer 30

divergent plate boundaries

Question 31

what are shield volcanoes made of and what is the lava Iike

Answer 31

formed by layers of basaltic runny lava which can flow long distances before solidifying so the volcano is low with gentle sloping slides

Question 32

what are explosions like for shield volcanoes

Answer 32

frequent but gentle eruptions produced under low pressure

Question 33

explain the differences between shield and composite volcanoes (4)

Answer 33

• shield are formed at divergent boundaries. composite are formed at convergent • shield are broad, gently sloping. composite are tall and thin • shield have frequent, gentle eruptions. composite have explosive eruptions • shield formed from layers of solid lava. composite formed form layers of lava and ash layers

Question 34

two ways that volcanoes can be predicted

Answer 34

- thermal imaging - seismometer

Question 35

define earthquake

Answer 35

a vibration of the earth's crust. tectonic plates try to push past each other, pressure is built up which is suddenly released

Question 36

what is magnitude measured with?

Answer 36

a seismometer

Question 37

what does it mean that the Richter scale is logarithmic

Answer 37

a magnitude of 5.0 is 10 times more powerful than 4.0