While our family has been travelling, we have been seeing lots of different volcanos. Active, Dormant and Extinct. There are many stages of volcanos, from the magma under the ground to the lava that erupts that produces igneous rock.
There are four layers of the earth. Inner core, Outer core, Mantle and the Crust. The lava that comes out of volcanos is from the Mantle. The molten rock under the ground is called magma, and the molten rock above the ground is called lava. Molten rock is melted rock. Magma is formed by the melting of rocks in the earths lithosphere (the crust and the top part of the mantle.) The Magma finds a vent in a volcano and makes the lava pool that you see in most photos of Mt Kailua. When the pressure builds up under the surface, the volcano erupts.
After the volcano has erupted and the lava has cooled, it forms igneous rock. Rocks like obsidian and basalt are made by volcanos like the ones in Hawaii, where the lava flows all the time. Other rocks like Scoria, which has lots of big holes in it, comes from explosive volcanos like Krakatau. Volcanologists can tell that New Zealand was once like Hawaii when it was younger, because they found the same type of hexagonal pillars in both countries.
There are three different types of volcanos. Active, Dormant and Extinct. An active volcano is one with a lava pool. It could erupt at any time. An example of an active volcano could be Mt Kailua or Mt Fuego. Mt Fuego is in Guatemala near Antigua. We are there at the moment and we can see it constantly puffing out smoke and ash. A dormant volcano does not have a lava pool. It probably last erupted thousands of years ago. An extinct volcano is one that hasn’t erupted in millions of years and probably won’t erupt again. Mt Maunganui is an extinct volcano. It last erupted 2.35 years ago according to Wikipedia.
So as you can see, volcanos have many stages and are very dangerous. The lava, igneous rock and the history that volcanos leave behind are extremely fascinating. All the stages that the volcano goes through to erupt to then form rock is incredible.