Cold magma helps predict volcanic eruptions

By Casey Frye, CCNN Writer

Mount Hood image
Volcanoes like Mount Hood can quickly go from dormant (not having erupted for a very long time) to active (likely to erupt again).

It seems like magma (underground molten rock) is always bubbling below a volcano, ready for an explosion at any moment. According to recent research, however, magma is actually not ready to blast forth in an eruption as lava (above ground molten rock). Instead, it tends to be stored in a cool place as sticky, peanut butter-like crystals.

Researchers came to this conclusion by studying crystals in lava from Oregon’s volcanic Mount Hood. They took samples from two past eruptions, 220 years ago and 1,500 years ago, and used special chemical signals to see how hot (or cold) the lava was when it was magma underground. They also used the chemical traces to determine how long the magma stayed at this temperature.

Based on their readings, the magma stayed in a cooler, peanut butter-like texture for thousands of years at a time, too sticky and sluggish to erupt from a volcano top. In fact, they calculated that crystals need to heat up by about 122-167 degrees Fahrenheit before they’re thin enough to move as a liquid. The only way this can actually happen is if fresh magma from deep in the Earth rises up and warms the crystals.

Though it stays in this sticky condition for thousands of years at a time, it only takes a matter of months before it’s ready to erupt. The researchers believe finding liquid magma near a volcano could be a good way to predict an eruption.

Featured image courtesy of Karlbert on Flickr. Image of Mount Hood courtesy of Oregon State University.