Download Chapter 12- section 1- Volcanoes and Earth`s moving

Chapter 12
Volcanoes- Section 1
Volcanoes and Earth’s moving plates
Volcano Definition
A volcano is an opening in Earth that
erupts gases, ash, and lava.
 There are more than 600 active
volcanoes.

Effects of Eruptions
Lava destroys everything in its path.
 Falling volcanic ash can collapse buildings,
block roads, and potentially cause lung
disease.
 Sulfurous gas can be released. This can
mix with water vapor resulting in acid
rain.

Pyroclastic Flow

Pyroclastic flow- volcanic ash and debris
flowing down the volcano.
How do volcanoes form?
They form from magma that reaches the
surface of the Earth.
 Vent- the opening in the Earth that allows
the magma to flow out.
 A crater- the steep walled depression
around the volcano’s vent.

Where do volcanoes occur?

Divergent plate boundaries-Iceland is part
of the Mid- Atlantic ridge so as the plates
pull apart the magma reaches the surface.

Convergent plate boundaries- when an
oceanic and continental plate subduct this
allows for volcano formation.
Hot spots

The Hawaiian Islands formed far from plate
boundaries but they formed from volcanic
activity.

In some areas, it is thought that the Earth’s
mantle and core are unusually hot.
Hot spot- hot rock at these areas is forced
toward the crust where it melts partially to
form a hot spot.

Hot spots