Volcanic magma simmers right before it erupts

Kristina D.C. Hoeppner / Flickr

Volcanoes are not easy to study. Scientists trek over debris fields to place networks of GPS that track the movement of the ground, record earthquakes caused by magma moving through the mountain and even gather lava. But all of this research is done on the surface. One major piece of data was missing: what happens inside of a volcano before it erupts.A new study, published in Science, used crystals in magma to create a temperature record of the inside of a volcano in New Zealand.

Why it matters: If scientists can understand the behavior of a volcano right before it releases lava, they may be able to predict the eruptions.

How they did it: Silicon crystals contain radioactive uranium and thorium whose decay can be used to determine the age of the crystals. Then, they looked at the distribution of lithium within the crystal to determine how often it was exposed to high temperatures. By combining the data, the researchers were able to create an extremely detailed timeline of temperatures inside a volcano before an eruption.

What they found:

For thousands of years, the magma inside of the volcano was cold (well, cold for magma) before temperatures skyrocketed to over 650 degrees Celsius. Not long after, the volcano would erupt. This is one piece of evidence in a debate over whether magma in volcanoes is always molten, or if it only becomes hot before an eruption. This supports the results of a previous,

similar study of Mt. Hood

, a volcano in Oregon.