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Explainer: The Different Types of Volcanoes on Earth
Even if you don’t live near a volcano, you’ve been impacted by their activity.
It’s estimated that more than 80% of our planet’s surface has been shaped by volcanic activity. They’ve helped create our mountain ranges, plains, and plateaus, and have even helped fertilize the land that we now use to grow crops.
These critical mounds come in many shapes and sizes. This graphic by Giulia De Amicis provides a brief introduction to volcanoes, explaining their different types of shapes and eruptions.
Types of Eruptions
A volcano starts to form when molten rock rises from a crack in the Earth’s surface, which often emerge along tectonic plate boundaries.
Magma rises to the Earth’s surface because it’s lighter than rock. When it surfaces or erupts, it’s referred to as lava.
There are various types of volcanic eruptions, depending on the lava’s temperature, thickness, and composition. Generally speaking, high gas content and high viscosity lead to explosive eruptions, while low viscosity and gas content lead to an effusive, or steadily flowing, eruption.
The Four Main Types of Volcanoes
Volcanoes vary in size and structure, depending on how they’re formed. Most volcanoes types fall into four main groups:
Shield volcanoes are built slowly, from low-viscosity lava that spreads far and quick. The lava eventually dries to form a thin, wide sheet, and after repeated eruptions, a mount starts to form.
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