1.Nature and Distribution

Question 1

Oceanic ridge

Answer 1

Plates are moving apart and magma is forcing its way to the surface cooling and forming a new crust
As the plates move further apart this crust is carried away from the ridge

EG Mid Atlantic ridge Iceland

Question 2

Subduction zones

Answer 2

Line of volcanoes that surrounds the Pacific Ocean associated with plate subduction
The deeper the oceanic plate descends the hotter surroundings become

This with heat generated by friction begins to melt oceanic plate into magma

Question 3

Subduction zones 2

Answer 3

Creates complex composite volcanoes and explosive volcanoes

If eruptions take place offshore a line of volcanic islands known as island arc appear

Question 4

Rift valleys

Answer 4

Constructive margins in continental areas
Areas of crust drop down parallel faults to form rift valleys
Through this thinning crust, magma forces its way to the surface to form volcanoes

Question 5

Hot spots

Answer 5

Concentration of radioactive elements below crust causes hot spots to develop
Plume of magma rises and this lava breaks through to the surface active volcanoes form above the spot