Why Do Volcanoes Erupt?

A volcano eruption is simply the resulting explosion of the heat and pressure that has built sometimes centuries in advance. Magma buried deep below the surface of the earth builds pressure until the volcano can no longer contain the pressure. Because the pressure must be expelled somehow, the liquid and heat build to a huge degree and force toward the surface of the earth.

There is much more than rocks and dirt below the surface of the earth. The earth has a core made of hot metal, and above that are two levels of what is called mantle. One top of the mantle rests a crust, which is made up of plates that sometimes force themselves into each other, creating mountains. This can also cause fractures to form just below the crust of these mountains.

Underneath the earth’s rocky crust, temperature and pressure become extremely high, causing the rocks beneath the surface to melt into a thick, hot substance known to scientists as magma. This hot rock rises because it is lighter than the solid rock in which it is encased, and it bubbles right below the surface of the earth. Over time, pockets of this magma begin to form.

Along with the magma, water and other gasses have dissolved into a vapor that becomes superheated due to the temperature of the magma, resulting in a build in the pressure of the magma pocket. Although the earth’s crust is extremely strong, the build in pressure causes weak spots in those mountains to explode, creating a volcanic eruption.

Types of Eruption

Volcanoes may erupt in many different ways, and these different types of eruptions are often named after the location where they were first observed. Volcanoes are actually named after the island of Vulcano in Rome.

Many people associate volcanic eruptions with these violent and explosive events. Strombolian eruptions result in giant pieces of rock being expelled through the volcano’s vent hole and often send lava arcing through the sky.

Hawaiian eruptions are less explosive, with lava flowing more slowly out of openings in the ground. Unlike the cinder cone shape of many volcanoes, these are much wider and less tall.

The most violent type of eruption known to man is the Plinian eruption, which shoots a giant cloud of ash and gases into the sky. In Plinian eruptions, the whole volcano (or a large portion of it) may collapse following the explosion. There are many other types of eruptions, including ones that occur under the sea.

Different areas in the world have volcanoes, from North and South America to Europe and Africa. One of the largest volcanic areas in the world is known as the Ring of Fire, a chain of volcanoes in the Pacific Ocean that form a giant semicircle. Hawaii is right in the center of the Ring of Fire.

The western coast of the United States is home to several famous volcanoes, as is Japan. However, the earth is not the only place where volcanoes are found. Mars has several dormant volcanoes on its surface, and Venus has many volcanoes that may or may not remain active to this day. Io, one of Jupiter’s moons, is the most active volcanic location in the entire solar system.