plate movement landforms

Question 1

what are shield volcanos

Answer 1

wide, gently sloping volcano formed by low viscosity lava spread over long distances

Question 2

what’s the other way a shield volcano can form

Answer 2

over a hot spot where heats the ground and melts, crust gets thinner and magma breaks through to a volcano- creates chain of volcanic islands

Question 2

what are the 4 steps of formation for shield volcanos

Answer 2

1) magma rises and reaches surface at constructive plate boundary
2)magma is basaltic (low silica) so low viscosity
3)on eruption lava is fluid so flows over long distances
4) each eruption spreads thin layer over wide area, cool and solidify

Question 3

what are composite volcanos

Answer 3

steep sided, cone shaped volcanos built from alternating layers of volcanic debris from eruptions

Question 4

process of composite volcano formation- 5 steps

Answer 4

1)oceanic plate subucts under continental
2)heat pressure & water release from sub ducting plate melting the surrounding layer of the mantle creating high viscosity magma
3) convection currents make magma rise creating shallow chamber
4) pressure builds due to gas expansion causing eruptions
5) process repeats reading alternating layers in a cone shape

Question 5

what plates can a composite plate not form on

Answer 5

continental- continental

Question 6

what is an oceanic trench

Answer 6

long, narrow, deep depressions at destructive plate boundaries, marking the subduction zone and deepest part of the ocean

Question 7

how does an oceanic trench form

Answer 7

1)at a destructive plate boundary denser oceanic plate subjects into asthenosphere
2)creates deep depression in ocean floor
3)continued subduction and compression deepen and maintain trench
4)friction+pressure along subduction zone cause earthquakes