Earth science

Question 1

asthenosphere

Answer 1

a partly molten layer in Earth’s upper mantle just below the lithosphere

Question 2

Continental Drift Theory

Answer 2

states the continents have not always been where they are today but have drifted there over millions of years

Question 3

crust

Answer 3

earths outermost layer formed by lighter materials, such as silicon and oxygen, which floats to the top during Earth’s early cooling period.

Question 4

earthquake

Answer 4

is a sudden ground-shaking release of built-up energy at or under Earth’s surface.

Question 5

epicentre

Answer 5

the point on Earth’s surface directly above the focus where an earthquake starts

Question 6

fault

Answer 6

large breaks in rock layers

Question 7

focus

Answer 7

the location inside Earth where an earthquake starts

Question 8

hot spot

Answer 8

is an area where molten rock rises to Earths surface

Question 9

inner core

Answer 9

earths solid centre

Question 10

lithosphere

Answer 10

the layer of Earth made up of the crust and uppermost mantle and ranging in thickness from 65 to 100 km

Question 11

magnetic reversal

Answer 11

a process in which Earth’s magnetic field, over thousands of years completely reverses its direction

Question 12

mantle

Answer 12

Earth’s thickest layer, lying just below the crust and making up 70% of Earth’s volume

Question 13

outer core

Answer 13

the layer below Earth’s mantle

Question 14

paleoglaciation

Answer 14

refers both to the extent of ancient glacier and to the rock markings left behind

Question 15

what is plate boundary?

Answer 15

where two tectonic plates are in contact.

Question 16

what are the 3 main types of tectonic plate boundaries?

Answer 16

divergent (spreading apart)
convergent (moving together)
transform (sliding by)

Question 17

name the four layers of Earth,, in order from inside out.

Answer 17

inner core
outer core
mantle
crust

Question 18

what is plate tectonic theory?

Answer 18

the theory that the lithosphere is broken up into large pieces that move and then rejoin.

Question 19

define primary wave (P- WAVE)

Answer 19

a type of seismic body (underground) wave that travels at 6km/s through Earth’s crust, causing the ground to move in the same direction of the wave’s motion

Question 20

ridge push is…

Answer 20

new material at a ridge or a rift pushes older material aside, moving the tectonic plates away from the ridge.

Question 21

rift valley

Answer 21

a steep-sided valley formed on land when magma rises to Earth’s surface at spreading centre

Question 22

seafloor spreading

Answer 22

the process in which magma rises to Earths surface, as it continues to rise, pushes older rock aside

Question 23

secondary waves (S-WAVES)

Answer 23

a type of seismic body (undergoes) wave that travels at about 3.5 km/s, causing perpendicular to the direction of the waves motion

Question 24

seismograph

Answer 24

a record of ground motion

Question 25

seismometer

Answer 25

devices that measure the amount of ground motion caused by an earthquake; also called seismographs

Question 26

slab pull

Answer 26

the pulling of a tectonic plate as its edge subducts deep into the mantle

Question 27

surface waves (L-WAVES)

Answer 27

seismic waves that ripple along Earth's surface.