Please enable JavaScript.
Coggle requires JavaScript to display documents.
Volcanos - Coggle Diagram
Volcanos
-
Subduction zones
Subduction zones are boundaries where two plates push up against each other, forcing an oceanic plate to subduct (sink) beneath another plate.
The subducting plate moves downward, carrying water trapped in sediments and rock into the mantle. When the plate reaches a depth of about 60 to 90 miles, Earth’s heat causes the water to boil.
The boiling water rises into the overlying mantle. There, the water lowers the melting point of the rock, which turns to magma.
-
Divergent boundaries
-
As the plates separate, hot rock from the mantle rises to fill the space between them.
The pressure on the rock decreases as the rock rises, causing it to melt.
The resulting magma erupts along the fracture between the plates and cools to form new plate material.
Hot spots
Hot spots are areas where columns of hot, solid rock rise slowly through the mantle.
At the top of the column, decompression melting turns the rock into relatively fluid magma with little gas.
-
Famous volcano eruption
-
Mount Tambora (1815) in modern Indonesia which killed over 100,000 people.
-
Tectonic plates
-
The roughly 30 tectonic plates “float” on the mantle that is located below the crust to form the outer shell of the Earth.
Volcanoes
Nearly all volcanoes form along the edges of tectonic plates at subduction zones and divergent boundaries.
-