News

Why do volcanoes erupt?

Deep within the Earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma.

Because it is lighter than the solid rock around it, magma rises and collects in magma chambers.

Eventually some of the magma pushes through vents and fissures in the Earth's surface.

A volcanic eruption occurs and the magma that has erupted is called lava.

Some volcanic eruptions are explosive and other are not.

How explosive an eruption is depends on how runny or sticky the magma is.

If magma is thin and runny, gases can escape easily from it, therefore this type of magma just flows out of the volcano.

Lava flows rarely kill people because they move slowly enough for people to get out of their way.

Lava flows, however, can cause considerable destruction to buildings in their path.

If magma is thick and sticky, gases cannot escape easily and the pressure builds up until the gases escape violently and explode.

In this type of eruption, the magma blasts into the air and breaks apart into pieces called tephra.

Tephra can range in size from tiny particles of ash to house-size boulders.


DISCLAIMER FOR COMMENTS: The views expressed by public comments are not those of this company or its affiliated companies. Please note by clicking on "Post" you acknowledge that you have read the TERMS OF USE  and the comment you are posting is in compliance with such terms. Your comments may be used on air. Be polite. Inappropriate posts or posts containing offsite links may be removed by the moderator.

Allentown, PA 18102

33°F

Overcast

TONIGHT

26°F

  • %

This Week's Circulars

Top Stories

Latest from the newsroom

More from the Newsroom