Ever wondered why some volcanoes explode violently whilst others just... Show more
Geography125 views·Updated May 29, 2026·2 pagesWhat are the Different Types of Volcanoes?
Bethany Cook@bethanycook_ocxl
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Types of Volcanoes: Shield vs Composite
Shield volcanoes are the gentle giants of the volcanic world. They've got slopes less than 10 degrees - imagine a warrior's shield lying flat on the ground. These volcanoes are made entirely of basaltic lava that's really hot and flows easily because it's low in silica.
The key thing about shield volcanoes is that they're not dramatic at all. The low viscosity magma flows smoothly down the gentle slopes, building up the volcano bit by bit. You won't find much explosive material here - eruptions are quiet, frequent, and produce loads of fluid lava through fissure eruptions on the sides.
Composite volcanoes are completely different beasts. They're tall, steep-sided cones made of alternating layers of lava and ash - like a geological layer cake. The magma here is andesitic with medium viscosity, so it doesn't flow far from the base.
Quick Tip: Remember that composite volcanoes are found at convergent margins where oceanic crust gets pushed under continental crust - think Mt. St. Helens!
These volcanoes are proper explosive. Higher gas content means pyroclastic flows and much more dangerous eruptions that can last ages.
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Volcanic Eruptions and Calderas
When volcanoes go completely mental, they can form calderas - massive circular craters up to 20km wide. This happens in three dramatic stages: violent eruptions empty the magma chamber, the top starts collapsing into the weakened space below, then the entire cone collapses. If it's near the coast, this can trigger tsunamis.
Volcanic eruptions happen when magma (molten rock from the Earth's mantle) rises to the surface because it's less dense than surrounding rock. As it rises, gas bubbles form inside it, and it searches for weak spots in the Earth's crust to break through.
Here's where it gets interesting: low viscosity magma flows out calmly as lava. But thick, high viscosity magma traps those gas bubbles, building up massive pressure until - BOOM! - you get an explosive eruption.
Remember: Viscosity is everything! Thick magma = explosive eruptions with pyroclastic flows, ash clouds, and volcanic bombs. Thin magma = gentle lava flows.
The nastiest eruptions produce pyroclastic flows , ash clouds that travel for kilometres, and volcanic bombs - basically massive chunks of hot rock flying through the air.
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Geography125 views·Updated May 29, 2026·2 pagesWhat are the Different Types of Volcanoes?
Bethany Cook@bethanycook_ocxl
Ever wondered why some volcanoes explode violently whilst others just quietly ooze lava? Understanding the different types of volcanoes and how they work is crucial for your geography studies - and it's actually quite fascinating once you get the hang... Show more
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Types of Volcanoes: Shield vs Composite
Shield volcanoes are the gentle giants of the volcanic world. They've got slopes less than 10 degrees - imagine a warrior's shield lying flat on the ground. These volcanoes are made entirely of basaltic lava that's really hot and flows easily because it's low in silica.
The key thing about shield volcanoes is that they're not dramatic at all. The low viscosity magma flows smoothly down the gentle slopes, building up the volcano bit by bit. You won't find much explosive material here - eruptions are quiet, frequent, and produce loads of fluid lava through fissure eruptions on the sides.
Composite volcanoes are completely different beasts. They're tall, steep-sided cones made of alternating layers of lava and ash - like a geological layer cake. The magma here is andesitic with medium viscosity, so it doesn't flow far from the base.
Quick Tip: Remember that composite volcanoes are found at convergent margins where oceanic crust gets pushed under continental crust - think Mt. St. Helens!
These volcanoes are proper explosive. Higher gas content means pyroclastic flows and much more dangerous eruptions that can last ages.
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Volcanic Eruptions and Calderas
When volcanoes go completely mental, they can form calderas - massive circular craters up to 20km wide. This happens in three dramatic stages: violent eruptions empty the magma chamber, the top starts collapsing into the weakened space below, then the entire cone collapses. If it's near the coast, this can trigger tsunamis.
Volcanic eruptions happen when magma (molten rock from the Earth's mantle) rises to the surface because it's less dense than surrounding rock. As it rises, gas bubbles form inside it, and it searches for weak spots in the Earth's crust to break through.
Here's where it gets interesting: low viscosity magma flows out calmly as lava. But thick, high viscosity magma traps those gas bubbles, building up massive pressure until - BOOM! - you get an explosive eruption.
Remember: Viscosity is everything! Thick magma = explosive eruptions with pyroclastic flows, ash clouds, and volcanic bombs. Thin magma = gentle lava flows.
The nastiest eruptions produce pyroclastic flows , ash clouds that travel for kilometres, and volcanic bombs - basically massive chunks of hot rock flying through the air.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Similar content
Most popular content: Volcanoes
2Most popular content in Geography
9Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan SiOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha KlichAndroid user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
AnnaiOS user