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Explaining the volcanic ash cloud

With this morning's news that a volcanic eruption in Iceland spewed an ash cloud toward the European continent, I followed up on my Q&A with NASA geophysicist Eric Fielding about the recent string of earthquakes.

It seems we're continuing our earth science lesson today.

Yup, lots of things going on these days.

So what's going on with the Iceland volcano. Is this within the range of normal activity?

Yes. The volcanoes in Iceland are among the most active in the world. Something is going off almost all the time. They have eruptions there usually every couple of years. This one seems to be a bit stronger than the other ones and the way the wind is blowing is carrying the ash towards the rest of Europe. The same thing happens fairly often along the chain of volcanoes in Alaska, but there isn't as much air traffic there.

Do you view volcanic eruptions the same way as you do earthquakes? Both are related to plate tectonics, but most scientists say earthquakes occur randomly. Does volcanic activity occur randomly?

It's generally random, but there can be swarms of activity in a given area at certain times.

Are we looking at a swarm of activity? It's probably safe to say the average news reader is feeling overwhelmed with earth processes lately.

Well, we can be pretty sure there's no correlation between the earthquake in China and the Iceland volcano. They're very far apart and the Iceland volcano has been erupting for several weeks. Today is just a burst of stronger activity. Plus the volcanoes in Iceland are underneath icecaps so that makes them produce more ash.

Glaciers can exert a lot of pressure. With climate change, would a melting glacier have any effect on the volcano underneath?

Well that's a possibility. Some people have suggested that melting glaciers due to climate change may be changing the stress on the magma erupting underneath. The thing about volcanoes is that the liquid rock inside is actually mixed with gas. So it's like a bottle of soda. When you take the top off a bottle of soda, the soda can expand rapidly. Especially if you shake it. The process inside a volcano is quite similar. If the gas releases suddenly it can cause an eruption.

So there would be more volcanic eruptions as climate change warms the earth?
Well there aren't that many volcanoes with glaciers on top of them. The ones in Iceland are the most extensive.

How long do you think this cloud of ash will be affecting Europe?
It depends on how long the wind blows.

More on the effects of the ash cloud.

http://www.globalpost.com/notebook/global-green/100415/explaining-the-volcanic-ash-cloud