Volcanoes are mountains that erupt. It is a vent in the earths crust through witch magma and gasses erupt. The word volcano comes from the god of fire, Vulcan. Volcanoes are all over the world. Most volcanoes are on the edge of the tectonic plates. Some volcanoes form on hot spots.
How are they formed?
Below the earths crust the pressure of the magma builds up. It then is forced up and it makes a vent in the earths surface. After it has erupt the lava then dry's up and forms a mountain
How does an eruption occure.
An eruption happens when the pressure builds up inside the magma chamber. When the pressure is high it makes the magma thick and gooey. When the pressure is low in the magma chamber the magma gets thin and runny. When it is like that, it flows more easily.
The different types of volcanoes.
There are different shapes and sizes of volcanoes. The three basic types are shield volcano, cinder cone and stratovolcano.
The shield volcano got its name because people thought it looked like the shape of an ancient warriors shield. The shield volcano is low in silica. They are shallow sided and has a flat bottomed crater. It has a long fluid lava flow witch can also flow into sea. Shield volcanoes can also be found on the ocean crust.
Cinder cone volcanoes are the smallest volcanoes. These volcanoes are formed by low silica magma that is runny. They are steep sided volcanoes that are cone shaped.
The stratovolcanoes are the most famous volcanoes. Mount St. Helens, Mt Vesuvius and Mt Fuji are stratovolcanoes. When it starts to erupt it begins with an explosion of ash and cinders. These volcanoes are often found on subduction zones.
Volcanoes are amazing. I feel lucky to be living in Auckland. There is one volcano that is nearby named Maungarei.
