Volcanoes

Why do volcanoes spew ash?

Where does all that ash actually come from, when a volcano spits a large ash cloud?

Volcanic ash is not as we know from the burning of organic substances, because the material that comes out of a volcano in large clouds does not meet that definition. The fine particles from a volcano are usually called ashes, because they resemble ashes and behave as ashes. But they are formed in a completely different way.

A volcano is created in places where magma comes from the interior of the earth through the earth's crust to the surface. The earth's crust is often thin here, and the pressure of the magma is great. As the magma makes its way out, the pressure from the environment keeps getting lower.

When it comes out, the pressure drops sharply in one fell swoop. The magma cools down very quickly and a fine, dry powder is created, which we call ash.

Part of the ash remains in the crater, while the rest can be hurled 20 kilometers into the air through the column of hot air above the volcano. The amount of ash varies greatly. Strato volcanoes with slow-flowing magma form more ash than volcanoes with fast-flowing magma.

Video: Stromboli Volcano Erupts, Spews Ash and Lava (April 2020).

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