What happens when volcanoes erupt under a glacier?

Volcanic eruption is a dangerous natural phenomenon on Earth, often releasing large amounts of lava accompanied by gas and ash with heat up to thousands of degrees capable of burning everything around .

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Even a series of flights and human activities on a large scale will be delayed by the impact of volcanic eruptions. However, that is when volcanoes operate on land. What about the volcanoes that are still active under glaciers and above giant ice sheets? Let's meet with geologist researcher Benjamin Edwards at Dickinson University to clarify the problem.

Photo of Eyjafjallajokull volcano eruption on April 17, 2010

Edwards is a geologist who studies volcanic issues. In a recent study, Edwards conducted experiments to investigate what happens when lava meets snow ice. He said: "When I was doing research in Russia, I was as close to the volcano as I could. At that time, if you exposed new lava to ice, the hissing sounds of steam and steam would straighten up. And you get the same thing when you put lava in cold water. " Below is a video for lava flowing on ice.

But the video above is just a stream of lava gently flowing to the surface of the ice. What if a volcano exploded and erupted from lava from below the ice? Here are the questions and answers of researcher Edwards.

Can the eruption easily penetrate the ice on the surface?

Schematic diagram of an active volcano below the glacier

Not necessarily so. Consider a volcanic area with an area of ​​about 70 square kilometers and this whole area is covered by 400 meters of thick ice. Each cubic meter of ice weighs about 1 ton (assuming 1 liter of ice weighs 1kg), inferring that the entire thick ice block will have a mass of 28,000,000 tons. Some have proposed the theory of breaking ice sheets up to hundreds of meters thick. But it seems that the probability is quite low for a volcanic eruption to penetrate a heavy and heavy ice in just a few seconds.

Does the eruption melt the ice block above?

Yes and this depends on the amount of lava flowing out. In theory, 1 cubic meter of lava could melt from 7.6 to nearly 10.7 cubic meters of ice. However, the lava is cooled very quickly so the amount of heat it emits also becomes less. Under rapid cooling conditions like in glaciers, a cubic meter of lava can only melt between 3.8 and 5.4 cubic meters of ice.

Most recently was the volcanic eruption at Grímsvötn in southeastern Iceland in 1996 and melted nearly 600 meters of ice. If the eruption could penetrate thick ice, some explosions could continue to occur, destroying some of the glaciers and firing debris into the air. Previously, there was a lot of evidence that the same incident happened at Alaska's Redoubt volcano that caused avalanches and shot ice chips.

How fast is lava melting ice sheets?

Image of glacier near Eyjafjallajökull volcano

This depends on what kind of lava is erupted by the volcano. Sometimes, volcanic eruptions flow lava flows in the form of tubes about 1 meter thick and 6 to 9 meters long. This model will release heat slowly and often melt the ice, creating a gap in the middle of the ice block. On the other hand, if volcanic minerals are small in volume, it is likely to cause ice to melt faster. Small pieces are quickly cooled, but at the same time they also heat things around faster. With tubular lava flow, a huge amount of heat still exists and time to completely cool is quite long. In the eruption at the volcano Grímsvötn, lava melted 600 meters of ice within 30 minutes and caused a massive flood.

What happens after lava flows on the ice surface?

You might think that each other flowing on the ice surface can be cooled quickly before it can flow away. In fact, this argument is not true. In lab tests, Edwards and his colleagues discovered that lava could move faster when it ran over the surface of the ice sheet, probably because the melting ice created an insulating layer. Help lava slide over it faster . And in real situations, an extra volcanic eruption is always covered by ice and ash. The ash will slow down the melting process and inadvertently help lava flow over the ice surface for up to several hours.

How does ice affect the amount of ash?

Dust ash from volcanic eruptions can create giant ash clouds

This is a very important question. The volcanic eruption of Barðarbunga in Iceland in 2010 caused authorities not only in the host country but also across Europe to be concerned about the effects of huge ash clouds that could cause mass flights. postpone. Scientists have always tried to estimate the magnitude of volcanic ash clouds to anticipate its effects on human life.

After the research process, there were two contradictory comments: One theory was that when lava was exposed to ice, steam explosions would make the ash particles smaller. The smaller the ash is, the more likely it is to move in the air, and this is a disadvantage for the aviation industry. Another idea is that when lava comes into contact with ice, it creates a lot of water vapor, condensing and binding ash particles together. Since then, the ash will be heavier and will not be able to fly away.

Video of Eyjafjallajokull volcanic eruption in 2010

Currently, both of these arguments are still debated by geologists. However, an equally important factor is the amount of ash produced at the eruption for the first time depending on the type of lava . Basalt lava flows are usually liquid, while other thicker and denser lava types tend to explode and produce more ash. Volcanoes in Iceland erupt in both types of lava, so the research to clearly identify the two hypotheses is therefore difficult.

Another problem is that the lava in the ice can cause very dangerous big floods . Volcanoes in the glacier region will create big floods in Iceland called jökulhlaups. But if the lava can penetrate the thick ice, the ash will definitely be released into the air. Especially the volcanic eruption in the glacier is located in the time of violent winds like jet-streams are active.

Typically, the Eyjafjallajokull volcano erupted in 2010, the amount of ashes flew up to meet the rays blown from the West toward Europe, causing a series of flights to be postponed to ensure safety. In contrast, the eruption in 2011 here did not cause much impact because the ashes encountered the winds blowing them towards the North Pole. In short, the effects of ash clouds depend on the winds that take them away.