It is estimated that more than 80% of Earth’s surface has been shaped by volcanoes. They’ve helped create our mountain ranges, plateaus, and plains, and have helped fertilize the land that we use to grow our crops.
A volcano begins to form when molten rock rises from a crack in the Earth’s surface, which often emerges along tectonic plate boundaries.
Magma rises to the Earth’s surface because it is lighter than rock. When it reaches the surface, it is referred to as lava.
There are different types of volcanic eruptions, depending on the lava’s temperature, thickness and composition. Usually, high gas content and high viscosity lead to explosive eruptions, while low viscosity and gas content lead to and effusive or steadily flowing eruption.
The four main types of volcanoes
Shield volcanoes are built slowly, from low-viscosity lava which spreads far and fast. The lava eventually dries to form a thin, wide sheet which starts to form a mount after repeated eruptions.
Stratovolcanoes are built relatively fast. This is because, in between lava eruptions, stratovolcanoes emit ash and rock, which helps add structure to the mound rather quickly.
Volcanic domes are the opposite to shield volcanoes and are formed when lava is highly-viscous. Since the lava can’t travel very far, it starts to pool around the volcano’s vent.
Cinder cones typically don’t release lava. Instead, their eruptions typically emit volcanic ash and rocks, known as pyroclastic products.
Volcanoes can be very beneficial. Once broken down, volcanic products create very fertile soil.
Volcanic eruptions can also cool our climate. When a volcano erupts, ash and sulfur gas from the eruption combine with water droplets and get trapped in the atmosphere for years which has a cooling effect.
www.visualcapitalist.com/cp/the-different-types-of-volcanoes