- Definition: Openings in the Earth’s surface that let out ash, gas and hot magma
- Etymology: From the name of the Roman god of fire, Vulcan
- Famous Eruptions: Novarupta (1912), Mount St Helens (1980), Mt Pinatubo (1991)
- Biggest Eruption: Mount Tambora on Sumbawa Island, Indonesia, 1815
- Famous Volcanoes: Mount Etna (Italy), Mount Fuji (Japan), Eyjafjallajökull (Iceland)
- Consequences: Tsunamis, flash floods, earthquakes, mudflows, rockfalls
- Statistics: More than 500 active volcanoes in the world
- Geography: Active US volcanoes are located mainly in Hawaii, Alaska, California, Oregon
- Chemistry: Volcanic gases include water vapor, carbon dioxide, sulfur dioxide…
- Movies: Joe Versus the Volcano (1990), Dante’s Peak (1997), Volcano (1997)
- Definition: Volcanoes Are Basically Ruptures of the Earth’s Crust
- Formation: Volcanoes Are Formed in Many Different Ways
- Types: There Are 4 Major Types of Volcanoes
- Shape: The “Typical” Volcano Shape Is Actually Just One of Many Volcano Shapes
- Unit: The Strength of a Volcano Is Measured by the Volcanic Explosivity Index
- Location: Volcanoes Are Usually – But Not Always! – Located Where the Tectonic Plates Meet
- Geography: Most Volcanoes Are Located in the Ring of Fire in the Pacific
- Activity: Not All Volcanoes Are Active
- Statistics: There Are 20 Volcanoes Erupting around the World Right Now
- Chemistry: Magma and Lava Are Basically the Same Thing
- Lava Is Not the Only Danger from Volcano Eruptions
- Volcanoes Can Have Quite a Growth Spurt
- There Are Many Different Types of Lava
- If You Thought that Earth Was Full of Volcanoes, Think Again
- Volcanoes Can Be Found in the Strangest of Places
- There is a Volcano Bigger than Mount Everest
- Large Volcanic Eruptions Can Be Quite Spectacular
- Volcanoes Are Probably More Dangerous than You Think
- A Supervolcano Could Destroy Life as We Know It
- Believe It or Not, Volcanoes Also Have Some Benefits
Volcanoes Are Basically Ruptures of the Earth’s Crust
Volcano facts show that the simplest way to define volcanoes is as large openings in the surface of the Earth – or any other planet, for that matter. These ruptures can stay inactive for ages or decades, and when they become active, they let out volcanic ash, gases, extremely hot lava and many other chemical compounds. Their eruptions can be incredibly violent and are sometimes spectacular to look at, but volcano facts show that they can also be devastating, and cause massive damage and loss of many lives.
Volcanoes Are Formed in Many Different Ways
Even though the basic principles of volcano formation are very similar, volcano facts show that the details can be slightly different. The main reason for the formation of volcanoes on Earth is the fact that its crust is broken into 17 major tectonic plates, which float on the Earth’s mantle. When these tectonic plates diverge or converge, they create the perfect conditions for the formation of volcanoes.
Depending on where this happens, the consequences are slightly different. For example, if a volcano is formed in the Mid-Atlantic Ridge, the formation of a volcano is a result of tectonic plates that pull apart from each other; in the Pacific Ring of Fire, the volcanoes formed are the consequences of tectonic plates coming together. In some other areas, volcanoes can also be a result of the Earth’s internal plates stretching and thinning. However, when two tectonic plates simply slide past one another, this does not usually cause a volcano.
There Are 4 Major Types of Volcanoes
Volcano facts show that all volcanoes share certain similar characteristics, but they are also very different in many ways. Their differences divide them into four major types: shield volcanoes, composite volcanoes (also called stratovolcanoes), cinder cone volcanoes, and lava domes.
Cinder cone volcanoes are basically the simplest volcanoes; they are usually smaller than other types of volcanoes and their eruptions are only about 1,300 feet high. Shield volcanoes are large and broad, and get their name from the fact that they look like a shield when looked at from above. The lava that erupts from them is of low viscosity, so it is thin and can travel great distances. Stratovolcanoes, also known as composite volcanoes, are huge and account for some of the world’s most famous volcanoes, such as Mount Fuji and Mount Rainier. They can grow several thousand feet tall, and when they explode, their eruptions can be extremely violent. Lava domes, or volcanic domes as they are also called, have very high viscosity lava, which means that the lava is too thick to flow very far. Lava that spills out of the volcano therefore usually just piles around it and causes a lava dome to grow. However, even though lava volcanoes sound a bit lazy and not all that dangerous, their explosions can be violent and extremely large.
The ‘Typical’ Volcano Shape Is Actually Just One of Many Volcano Shapes
When we think of a volcano, we usually have a very specific shape in mind – a tall, large cone-shaped mountain that spills out lava. However, volcano facts show that only one group of volcanoes look like this. Other shapes of volcanoes include wide plateaus, which are lower and less steep, so they do not really resemble our typical vision of a volcano; fissure vents, which are volcanoes with cracks that dispel lava; and bulging dome shapes, which are much smaller and lower than what we usually think of when picturing a volcano.
The Strength of a Volcano Is Measured by the Volcanic Explosivity Index
We already know that different volcano eruptions can be more or less intense, but volcano facts reveal that their intensity can be quite accurately measured. The tool for these measurements is the Volcanic Explosivity Index (VEI), which was devised by Chris Newhall from the US Geological Survey and Stephen Self from the University of Hawaii in 1982.
The Volcanic Explosivity Index provides a relative measure of the explosiveness of volcanic eruptions by using data such as volume of products, eruption cloud height, and qualitative observations. One of the most interesting volcano facts reveals that the scale is open-ended; the smallest value is 0 and is given to non-explosive eruptions, defined as less than 10,000 m3 (350,000 cubic feet) of tephra ejected, and the largest value given in history so far has been 8, representing a mega-colossal explosive eruption ejecting 1.0×1012 m3 (240 cubic miles) of tephra with a cloud column height of over 50 km (31 miles).
Volcanoes Are Usually – But Not Always! – Located Where the Tectonic Plates Meet
Volcano facts show that volcanoes are almost always formed where the tectonic plates of the Earth converge or diverge, but that is not always the case. True – most volcanoes still occur on the meeting points of tectonic plates, but they can also form in other areas. These are points that contain abnormally hot rock inside the Earth, which facilitates the formation of volcanoes. They are known as mantle plumes or hotspots, and are found at a number of locations all around the world, with one of the most notable spots being in Hawaii.
Most Volcanoes Are Located in the Ring of Fire in the Pacific
While volcanoes can be formed anywhere where tectonic plates are meeting or separating, or even in other places known as hotspots, volcano facts reveal that there is a part of the Earth where the chance of volcano formation is much, much greater. This area is known as the Pacific Ring of Fire and it is the home to a whopping 75% of the Earth’s active and dormant volcanoes.
The Pacific Ring of Fire, which stretches for 25,000 miles in length, is not only known as the home to many, many volcanoes – the current total is 452 volcanoes -, but is also famous for its earthquakes. The reason for all this activity in the area is the fact that there are many tectonic plates meeting and separating in the Pacific Ring of Fire, which consequently makes it a very dangerous place to live in.
Not All Volcanoes Are Active
Even though our typical idea of a volcano is a mountain exploding with lava and smoke, volcano facts reveal that the actual picture can be quite different. Apart from active volcanoes, there are also those that are simply waiting for their turn to erupt.
For a volcano to be classified as active, it needs to have regular activity and it has to have erupted recently. The definition of “recently” varies greatly; some scientists even define recently as within a period of thousands of years. Dormant volcanoes are those that
have had recent activity, but are currently quiet – however, they could erupt again at any time. Then there are extinct volcanoes, which are not likely to erupt again and generally no longer have a lava supply.
There Are 20 Volcanoes Erupting around the World Right Now
At any given moment, there are around 20 volcanoes erupting all over the world. Some are erupting for the first time ever, some are experiencing ongoing eruptions, some cause serious problems and pose a great danger to the nearby population, and some eruptions go by practically unnoticed.
It is estimated that every year there are between 50 and 70 volcanic eruptions. Geologists believe that around 1,300 volcanoes have erupted in the past 10,000 years; however, the true number could be much greater. A large number of eruptions go completely unnoticed, mainly because of their location, so the total number of volcanoes that have erupted in the past 10,000 years could actually be closer to 6,000.
Magma and Lava Are Basically the Same Thing
Not many people can tell the difference between lava and magma, and volcano facts reveal that there is a good reason for that: they are basically the same thing – the only real difference is their location.
Magma is the hot liquid rock that is located around 18.5 miles beneath the surface of the Earth. Since magma is lighter than the rocks that are surrounding it, it rises above them, finds its way to the Earth surface through the cracks in the crust, and erupts. Once it erupts, it is called lava. To sum things up, the exact same compound is called magma while it is still under the surface of the Earth, and it is called lava once it is above the surface.
Lava Is Not the Only Danger from Volcano Eruptions
Extremely hot lava may seem to be the most dangerous part of volcanic eruptions, but volcano facts show that it is definitely not the only one. When volcanoes erupt, it is not only lava that is released into the surroundings; there are also hot gases and lots of volcanic gases, which can be just as dangerous and can cause a number of problems.
Volcanic ash can be as fine as 0.063 mm per particle – or it could be formed out of huge rocks; the largest are called volcanic bombs and can have a diameter of 20 feet. These rocks erupt from the volcano with great power and shower the area around the volcano, which can cause terrible damage. But even the fine volcanic ash, no matter how insignificantly small it appears, can cause huge problems. It can travel for hundreds of miles in the air and cause problems in areas far away from the primary volcanic eruptions – and it can stay aloft for years. Some consequences of volcanic ash include obscuring light from the sun, which can cool the Earth’s atmosphere, and volcanic ash can also collapse roofs, kill animals and crops, or cause problems for air traffic.
Volcanoes Can Have Quite a Growth Spurt
Even though volcanoes seem like slow-growing mountains, they can actually be quite quick when it comes to gaining size. Some of them can grow literally overnight. One of the most interesting examples revealed by volcano facts is the cinder cone volcano called Paricutin. It suddenly appeared in a Mexican cornfield on February 20, 1943. By the end of that year, it had grown up to a whopping 1,100 feet, and ended its growth spurt in 1952, when it was 1,400 feet tall. This means that in its first year, the volcano grew more than 3 feet a day, which is definitely an impressive rate, especially for a volcano!
There Are Many Different Types of Lava
Most people think that there is only one type of lava, but volcano facts show that they are wrong! The characteristics of lava depend on its composition; its mineral content can vary greatly and thus determine its consistency. Lava can be thicker, viscose and slower, or thinner, more viscose and quicker.
Even though all types of lava are insanely hot, there are significant differences between temperatures of different types of lava. The coolest types of lava can erupt at temperatures between 1110 and 1380° F, while the hottest types of lava can reach temperatures up to 2200° F.
If You Thought that Earth Was Full of Volcanoes, Think Again
Volcano facts reveal that we definitely do have some stunningly big volcanoes on Earth, but that our planet is far from the most fascinating object of the solar system when it comes to volcanoes. The most intense volcanic activity actually occurs on one of Jupiter’s moons, called Io. It is covered with more than 400 volcanoes, and volcano facts show that its landscape is always changing due to volcanic activity.
And the largest volcano is our solar system? The Earth is once again not the winner of the competition: the largest volcano in our part of the universe in actually located on Mars. It is called Olympus Mons and it is 373 miles wide and 13 miles high. Its size is especially fascinating considering the fact that Mars does not have tectonic plates. So, how was this stunning volcano formed? Volcano facts reveal that it is the result of a single hotspot, which has invested billions of years into creating this huge volcano.
Volcanoes Can Be Found in the Strangest of Places
Since the majority of the Earth’s surface is covered with water, it makes sense that the majority of volcanoes lie under the surface of our planet’s oceans. They truly lie in the strangest of places, such as on the ocean floor or even under icecaps. Volcano facts statistics show that there are over 5,000 active underwater volcanoes, which produce more than 75% of all lava that erupts on our planet every year.
The volcanoes that lie on the floor of the oceans are known as submarine volcanoes and can sometimes turn into islands, after they have been growing for years. The Hawaiian Islands are actually volcanoes that have broken the surface of the water and became islands. At this moment, there is a new Hawaiian island forming around 30 miles off the southeast coast of Hawaii. But don’t start looking for plane tickets just yet – it will only breach the surface of the ocean in a couple of hundred thousand years.
The volcanoes found under icecaps are known as subglacial volcanoes. The area of the world most famous for this type of volcano is Iceland, but they can also be found in Antarctica, and some older formations of this type are located in British Columbia and Yukon Territory in Canada.
There is a Volcano Bigger than Mount Everest
Even though the largest and most impressive volcanoes of our solar system are not located on Earth, our planet does host some spectacular volcanoes. For example, the tallest volcano on Earth is Hawaii’s Mauna Kea, which boasts an elevation of 13,800 feet. But that doesn’t mean that this is the full height of this stunning volcano; measured from the sea floor, it is actually 33,000 feet in height – which is bigger than Mount Everest.
The Hawaiian Islands are also the home of the largest volcano in volume; it is Mauna Loa, a volcano that is made up of around 18,000 cubic miles of material.
Large Volcanic Eruptions Can Be Quite Spectacular
Volcanic eruptions can be extremely dangerous and terrifying, but volcano facts reveal that they can also be quite a spectacular sight. The ash they send into the air can fly as high as 17 miles above the surface of the Earth. One of the most stunning eruptions took place in 1991, when Mount Pinatubo ejected more than 1 cubic mile of material, which consequently created a column of ash rising 22 miles high into the atmosphere.
These extremely large eruptions also have significant consequences for the Earth’s atmosphere; volcano facts show that the largest eruptions have actually managed to cool the Earth. Average temperatures on our planet have decreased by around half a degree as a result of major eruptions.
Volcanoes Are Probably More Dangerous than You Think
The fact that volcanoes are dangerous probably isn’t really news to anyone – but we would certainly struggle to imagine just how dangerous they can be. Some of the most devastating volcanoes in history killed thousands of people and caused terrible devastation over a large area.
One of the oldest deadly volcanoes recorded is probably the Vesuvius; when it exploded in AD 79, it destroyed the towns of Pompeii and Herculaneum, and killed 16,000 people. One of the most deadly volcano eruptions ever was that of Krakatoa, which erupted in 1883 and created a tsunami that killed 36,000 people. Only a couple of decades later in 1902, Mount Pelee on the island of Martinique buried a town with 30,000 people. Toba, the largest explosion on record, erupted 73,000 years ago, released more than 670 cubic miles of material, and plunged our planet into an ice age.
A Supervolcano Could Destroy Life as We Know It
As if normal volcanoes do not seem terrifying enough, there are also much larger and much scarier versions of them called supervolcanoes. Toba was an example of a supervolcano. Luckily, there has not been an eruption of a supervolcano for more than 70,000 years, but if one were to erupt, it would probably wipe out most of the Earth as we know it. Supervolcano eruptions are thousands of times larger than normal volcanic eruptions and have long-lasting changes, so they can significantly change the face of the planet and cause extinction of many species.
Believe It or Not, Volcanoes Also Have Some Benefits
It sounds unlikely, but it is true: even though volcanoes are mostly considered dangerous and thus undesirable, they also have some benefits. For example, they can be harnessed for geothermal energy. Iceland, one of the most volcanically active regions in the world, actually generates a large part of its energy from geothermal energy. Volcanoes are also able to create brand new islands, such as the entire Hawaiian chain of islands.
Volcano ash can be very harmful, but on the other hand, it enriches the soil and makes it ideal for farming. Volcanoes also produce many precious gems and rocks, such as opals, obsidians, and pumice stones.
Volcano Facts — Facts about Volcanoes Summary
Volcanoes are openings in the Earth’s surface that let out ash, gas and hot magma when they erupt. Their name comes from the name of the Roman god of fire, Vulcan. Eruptions of volcanoes can be extremely dangerous; some of the most famous eruptions include Novarupta in 1912, Mount St Helens in 1980, and Mt Pinatubo in 1991. The eruption of Mount Tambora on Sumbawa Island, Indonesia, in 1815 is considered the largest volcanic eruption in recorded history. The most significant consequences of volcanoes include tsunamis, flash floods, earthquakes, mudflows, and rockfalls. There are currently more than 500 active volcanoes in the world, and most active US volcanoes are located in Hawaii, Alaska, California, Oregon and Washington.