Volcanoes and types of lava

Question 1

What are Volcanoes?

Answer 1

Volcanoes are openings in the earth’s crust through which lava, ash and gases erupt. Like earthquakes, they are closely associated with plate margins (60% are found in these locations). As tectonic plates move, pressure builds and hot magma and gasses push up from the mantle to the Earth’s crust. When the magma reaches the Earth’s surface, it is called lava.

Question 2

Basaltic Lava

Answer 2

Flows like water (Low viscosity)
1000-2000*c
thin + runny
Associated at divergent boundaries
Locations include: Shield volcanoes, ocean hot spots, and mid ocean ridges
Effusive/less explosive
Eruptions are more frequent
Gentle/effusive eruption
Creates shield Volcanoes

Question 3

Rhyolitic Lava

Answer 3

High viscosity
High amount of Silica
650-800*c
Associated at convergent boundaries
Locations include: Super volcanoes, composite cone volcanoes.
Violent explosions
Eruption type = magma blasted apart, shakes to create volcanic ash.
Creates composite/straxo volcanoes

Question 4

Three Primary Volcanic hazards

Answer 4

Pyroclastic flows = a fast-moving current of hot gas and volcanic matter
Lava flows
Could cause ice melting - Jokulhaups = Rainwater that builds pressure ad causes flash flooding and widespread landform modification