1. Landforms Made from Volcanoes

2. Lava Plateaus Sometimes, lava does not form mountains
Lava flows out of crust and collects in one area, forming a high plateau

4. Calderas
Enormous eruptions can empty the magma chamber under the volcano
With nothing left for support, the mountain collapses

5. Caldera
The hole left over is a caldera

6. Soils from Lava Initially, lava hardens and destroys plants.
Eventually, the lava breaks down and produces good soil that supports plants.

8. Landforms from Magma
Sometimes, magma does not leave the vent and gets trapped under ground.
Eventually, all the other rock around the lava wears away and leaves the hardened magma behind.

9. Landforms from Magma
Volcanic necks form from magma that hardens in the volcano pipe.

10. Landforms from Magma
A batholith is a large rock that forms when a large body of magma cools in the crust.

11. Landforms from Magma
Dome mountains are formed when magma is blocked by rocks.
The magma pushes rock layers up, making small mountains.

12. Volcanic Activity

13. How Does it Erupt? Volcanoes are like cans of soda pop
Lots of gas is trapped inside the magma under pressure
During an eruption, the gases rush out and carry magma with them

14. Inside a Volcano
Volcanoes have a pocket of magma beneath is and cracks where magma can force through
Magma sits below
the volcano in a
magma chamber

15. Inside a Volcano Magma travels to the surface through a pipe
Magma and gases
leave through a
volcano vent

16. Inside a Volcano A lava flow is the area covered by the moving lava
A crater forms at the top of the volcano around the vent

17. Characteristics of Magma
How forceful an explosion is depends on:
How much gas is in the magma
How thick or thin the magma is?
Temperature
Silica content

18. Characteristics of Magma
Magma that is thick flows slowly.
The hotter the magma, the faster it flows.

19. Silica Earth’s crust and mantle are mostly made of silica
The more silica in
the magma, the thicker
it is

20. Silica
Magma with a lot of silica makes light-colored lava that is very thick
When high silica lava cools, it makes rocks like rhyolite, pumice and obsidian

21. Silica Magma that does not have much silica moves quickly and is thin.
Low silica magma is dark colored and makes rocks like basalt