What Causes A Volcano To Form And Then Erupt?

Volcanoes — nature’s creator and destroyer.

The lava-spewing explosive land forms can cause devastating damage but also produce many islands in their wake—including the Hawaiian islands.

So how exactly do volcanoes work?

It was once thought that volcanoes were mountains filled with fire.

But modern science has proven that they’re actually openings to the Earth’s red-hot interior.

According to the U.S. Geological Survey, there are about 1,500 active volcanoes on the planet today.

Many of which are located along the Pacific Rim in what’s known as the “Ring of Fire”.

Wonder if this is what Johnny Cash was singing about all along.

But how do volcanoes form in the first place?

It all has to do with the Earth’s layers.

You see, the Earth’s outermost layer—the crust—is made up of a bunch of different shifting pieces called tectonic plates, which together with the upper mantle, are referred to as the lithosphere.

Think of them as puzzle pieces.

These plates flow on top of the Earth’s mantle, which is composed of hot dense rock.

The reason tectonic plates shift at all is actually because of the mantle’s temperature and how much hotter it is closer to the center than the top of the Earth.

Now, volcanoes typically appear along destructive and constructive plate boundaries.

A destructive plate boundary is where oceanic and continental plates move together, forcing the oceanic plate under the lighter continental plate.

Meanwhile, constructive plates are ones that move apart.

Volcanoes form here as magma rises up to fill the gap.

Once magma reaches the Earth’s surface, it becomes lava.

And once that lava cools, it leaves behind new rock.

So as more eruptions happen over time, a pile of this cooled lava rock builds up in a cone shape and forms a volcano.

So how come some volcanic eruptions are violent and explosive while others are smooth and slow-moving?

Well, that depends on the magma.

If magma is thin and runny, gases are able to escape from it which allows for a smoother flow.

These types of volcanic eruptions are less dangerous than the explosive kind since they give people enough time to get the heck out of the way.

But if magma is thick and sticky, gases are stuck.

This creates a huge pressure buildup until the gases can escape, which results in a very violent release.

In these kinds of eruptions, magma will explode into the air and break apart into rock fragments called tephra which can vary in size from tiny pieces to the size of a house.

And these clouds of tephra can move fast, destroying virtually everything in their path.

Even worse, if this ash mixes with rain or snow, it can create mud flows, which can bury entire communities.

So, what do you do if you’re caught near a volcanic eruption?

Well, if you already live near an active volcano, you should probably have goggles, a mask, and emergency kits always on hand.

Know your evacuation route and evacuate per the directions of authorities in order to stay clear of flows and debris.

Volcanoes are just another reminder of the duality of nature.

Think you’ll be visiting a volcano any time soon?

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