How to and Why? What are Volcanoes? Causes, Types, and More!

//How to and Why? What are Volcanoes? Causes, Types, and More!

welcome to i am your target demographic and welcome to our video on volcanoes, the firstin a series focusing on natural disasters, hoping to explain them in a way that is easy to understand. this is extremely simplified, so it may help you understand the basics but it’s not intended to help you with all the scientific nuance, as we skip over some of the more complicated bits. this is a zoomed out picture of what causes volcanoes and the types of volcanoes you might see. let’s start with how volcanoes are created. these are some of the leading theories but some of this is contested because it’s hard to observe something that happens over such a long span of time. here’s three examples of what could cause a volcano. this super simple image contains the land and water on the surface of a crust, with the magma underneath. i’m not a graphic designer, as you can tell. in some cases, two pieces of crust move towards each other, as tectonic plates are moving along the surface of the earth. over thousands, maybe even millions of years, the crust smashes together and pushes down in the magma, heating it up and creating an excess of magma, that needs a release, so it pushes up through the crust and erupts. these plates can also move away from each other, splitting apart and causing new magma to rise to the surface.

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this sometimes results in vents underwater or even underwater volcanoes, which can still erupt in the same way that an above ground volcano can. now our third theory is about hotspots, which is basically an area of extreme heat that hits the crust and as the magma slowly cools down, it builds island and mountains. this hotspot doesn’t move but the crust does, so as the plates move, the hotspot slowly builds a volcanic range of mountains and potentially volcanoes. again, this is just a popular theory for ranges of volcanic action such as areas of hawaii. now let’s zoom in and start looking at volcanoes more closely. they can be formed in many ways. we’ll start with what are called shield volcanoes. these are usually created by slow magma flows, creating a shield like shape. they tend to not explode in the same ways that other volcanoes do. we also have lava domes, built by extremely thick lava that cools quickly, so it doesn’t travel far and builds up into domes and rugged peaks. these volcanoes can erupt violently, though lava doesn’t travel far. there are also things called fissure vents, which are long flat fractures that allow lava to emerge, usually not exploding. sometimes mineral fragments can build up around a vent and create what’s called a cinder cone volcano, building quickly. they tend to have a bowl-shaped crater at the top, filled with this rocky debris. if they erupt, they tend to only erupt once, but there have been cases of them erupting many times. these often exist on the outskirts of other larger volcanoes. next we have stratovolcanoes or composite volcanoes, called this because they’re a composite of many alternating cycles, where they might erupt and the lava hardens to create a new layer and then the process repeats. they have very threatening clouds of ash that can follow, as they tend to be incredibly tall and the pressure is very great.

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the largest volcanoes are appropriately called supervolcanoes, where the magma rises but is unable to break through, so the volcano grows and grows until the pressure is extreme. these volcanoes are the ones that can end civilizations, make species extinct, and even change the climate, such as triggering ice ages, the ash in the air stopping the sun from properly heating the earth’s surface. now let’s talk about some of biggest or most significant volcanoes we know of. in the united states, we have yellowstone in the state of wyoming. yellowstone has a supervolcano under the surface that heats the water and land above it, creating the geysers and hot water springs that tourists visit yellowstone to see. the last time it erupted was about 640,000 years ago, which caused the area to collapse down and be buried how it is today. it’s unsure if the volcano will ever erupt again, but if it did… it would cover most, if not all, of the united states in ash and the closest states would be devastated. while we’re in the mainland united states, we should discuss one of the most recent volcanoes there, the 1980 eruption of mount st. helens in washington state, deemed the most destructive volcanic eruption in the united states, at least since the civilized world. the ash fell on 11 nearby states and caused billions of dollars in damage, killing 57 people. moving to italy, we look at mount vesuvius. this volcano erupted regularly in 20 year intervals, give or take, but it last erupted in 1944, meaning we’re a bit overdue. this is the volcano that erupted in 79 ad and buried the city of pompeii, leaving human-sized voids in the ash and petrified magma, allowing scientists to create molds of these people in their last moments. they are still excavating and discovering more about the city.

the largest recorded volcanic explosion is mount tambora in indonesia. this explosion in 1815 was so loud that it was heard more than 1,200 miles away and killed over 71,000 people. this volcano is indeed still active and is one of the tallest peaks in indonesia today. many of us likely don’t have firsthand experience with volcanoes so what we learn about them, we learn from movies and television. during the golden age of natural disasters movies, we got gems like dante’s peak, which created a fictional volcano in a fictional city. this movie did a lot of things right but its characters managed to survive feats that should have killed a normal person. in reality, when ash falls, it’s microscopic glass that would kill nearly anyone or anything that inhaled it, but i guess that doesn’t make for exciting entertainment. this same qualm came up for the film volcano, in which a giant volcano strikes los angeles, something that is also scientifically near impossible. the fault lines that cause earthquakes are not the same type that might cause volcanoes. not traditionally, not commonly. but again, entertainment. so hopefully this helps you understand volcanoes a little more. if you’re interested, seek out deeper research, this was meant to be a superficial look not a deep dive. make sure you subscribe as we’re going to be adding more natural disaster content soon! thanks for watching!

2018-07-12T01:41:22+00:00 July 12th, 2018|Categories: How To.. for My Online World|Tags: , |