12.2

Question 1

lithosphere,

Answer 1

which ranges

in thickness from 65 to 100 km

Question 2

crust

Answer 2

early Earth cooled, the lighter elements, such as silicon and oxygen, separated
from the molten material, floated to the top, and formed the layer we know
today

Question 3

asthenosphere

Answer 3

a partly molten layer in the

upper mantle.

Question 4

mantle convection

Answer 4

one of the

driving forces behind plate movement.

Question 5

ridge

push

Answer 5

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

Question 6

Subduction

Answer 6

the action of one plate pushing below another

Question 7

subduction zones

Answer 7

Area of subduction ,typically experience

large earthquakes and volcanic eruptions

Question 8

slab pull

Answer 8

as the edge of a tectonic

plate subducts deep into the mantle, it pulls the rest of the plate with it.

Question 9

plate boundary

Answer 9

A region where two tectonic plates are in contact

Question 10

Divergent plate boundaries

Answer 10

mark the areas where tectonic

plates are spreading apart

Question 11

diverging plates

Answer 11

Plates that are

spreading apart are known

Question 12

focus

Answer 12

Location where the earth quake starts

Question 13

epicentre

Answer 13

e point on Earth’s surface directly above the focus.

Question 14

Shallow focus

Answer 14

0-70, more extreme because it is closer to the top

Question 15

intermediate focuss

Answer 15

70- 300 km not as bad

Question 16

deep focus

Answer 16

past 300 km

Question 17

composite

volcano

Answer 17

The cone shape results from
repeated eruptions of ash and lava, which build up layers, or
strata, much like layers in a cake

Question 18

shield volcanoes

Answer 18

Largest volcanoes Shield volcanoes do not occur at plate boundaries but instead form over
hot spots.

Question 19

Rift eruptions

Answer 19

occur when magma erupts through long cracks in the

lithosphere