It's time again for the A Moment of Science mailbag. A listener writes:

Dear A Moment of Science,

I've always been fascinated by volcanoes. So I was wondering: How well can scientists predict when and where a volcano will erupt?

There are a few well known warning signs, such as earthquakes in the vicinity of a known volcano. And, of course, smoke rising from a volcano.

Mastering Prediction

But a study out of the UK could give scientists an even better idea of how to predict eruptions. The researchers were looking at volcanoes along the mid ocean ridge a long chain of volcanoes lined up along where two of the Earth's tectonic plates pull apart.

Specifically, the researchers looked at the magma chambers beneath the volcanoes to see how they channel magma up to the surface.

Computer Models

Using satellite images, they built computer models and found that magma chambers can exist only .62 miles underground. That's really shallow, considering that earlier models had shown that magma chambers along the rift lay much deeper.

The satellite images and computer models also revealed that the ground near a volcano often begins rising and swelling about four months before an eruption. Measuring group uplifting is key to predicting eruptions, although these precursors don't always occur before an eruption.

Volcanoes along the mid ocean ridge erupt often, usually underwater, creating new crust. Studying the plumbing systems beneath these volcanoes helps scientists better understand how the Earth renews its surface.