So, you’ve probably heard the word “volcano” being tossed around a lot lately because of what is happening in Hawaii. The Kilauea volcano started erupting on May 3, 2018 and has been going strong ever since.
But what exactly is the reason behind why a volcano erupts? The short answer is pressure, but what does that mean?
What Are Volcanoes?
Volcanoes are sudden, violent outbursts of molten rock (magma) that come to the surface through fractures in the earth called fissures. They are generally found where tectonic plates meet or subduct.
How Do Volcanoes Occur?
There is no one single answer as to why volcanoes occur all over the earth, but it is generally understood that they occur on hot spots (areas where magma bubbles up from below the surface) and plate boundaries—where tectonic plates meet or subduct.
The plates push together and form a boundary: thus, we call it a plate boundary. It is where volcanic activity is most common.
All volcanoes erupt because of pressure: that is, lava and other magma pushing upward against the weight of the earth’s crust and surface. This pressure builds until there is a rupture and an eruption occurs.
There are many types of volcanoes (shield, cinder, composite) and these different kinds occur for a variety of reasons. However, they all erupt because pressure builds up below the surface until it finds its way through and releases.
The Stages of Volcanic Eruption
As lava builds up pressure beneath the surface, it finds its way through fissures in the earth’s crust. This is known as an effusive eruption.
During this time, there may be earthquakes and steam explosions that release some ash into the air. The magma typically does not come to the surface during this period because it is not yet very molten.
As more and more pressure builds up, the eruption becomes explosive. This is when hot ash and rock fragments called tephra are ejected from the volcano. These may be only a few feet or several hundred feet above ground level, depending on the type of eruption.
Volcanoes are dangerous and unpredictable, but as long as there isn’t any misinformation, staying safe during an eruption is not difficult. Keep calm and enjoy the lava!