Tamsyn Mather

So we have lots of well-monitored volcanoes.

You get a lot of really useful data.

So seismic data, which is the very small tremors and very small earthquakes that you get when magma or gas move in the Earth's crust, gives us lots of really useful information.

And then the changing shape of volcanoes is also really important for us.

So just an example, in 1980, before the Mount St.

Helens eruption, it kind of blistered up like a boil on the side of the volcano.

And then there was a small earthquake and it was from that swelling that the eruption initiated.

So we can pull all these different strands together in order to make a prediction that a volcano is very likely to erupt.

But it's only generally a forecast.

It's a bit like weather.

We can't be sure.

And the other challenge that we have is that we might be able to say it looks like it's going to erupt in the next month.

But actually saying it's going to erupt in two days time, which is a really helpful piece of information if you want to evacuate a big city, is much more difficult to do.

That's another big challenge.

And often we go back and study its past behavior in order to try and understand its future behavior.

And sometimes we can use things like how much it's deformed, how much it's swollen up to give us some clues about how much magma has arrived in the system.

Well, in some places, yes.

So the USGS do a great job monitoring the US volcanoes.

They have a lot of resources and a lot of expertise and people monitoring that.

In some parts of the world where there are fewer resources, volcanoes are not as well monitored.