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Scientists work to understand, predict volcanic eruptions

Warmer temperatures are melting glaciers that sit like pressurized lids on some of the world’s most volatile volcanoes.

In Iceland, one of the few countries that actively monitors its volcanoes, glaciers pound the Earth, geophysicist Frestein Sigmundsson told Bill Whittaker. Glacier retreat in Iceland is stirring up more magma beneath the Earth’s crust.

“Glacier retreat can increase the likelihood of eruptions,” Sigmundsson said.

Iceland, known as the land of fire and ice, has dealt with two eruptions in recent years. In 2021, The geldingali burst out. Chunks of molten rock the size of car wheels in the air. Lava erupted through nine vents and poured into the valley for months.


Volcanoes of Iceland

60 minutes

In early August 2022, a new fissure opened and the same volcano erupted again.

Both eruptions were highly unusual, said Kristin Jonsðir, head of earth science at the Icelandic Meteorological Office. Months before the eruption, magma stirred beneath the earth and triggered thousands of earthquakes. Typically, these seismic storms reach a crescendo before erupting. Instead, they went silent – only erupting when the tremors stopped.

“So this was something we didn’t expect because before most eruptions we see an increase in the process,” Jonestyr said. “So the closer we get to the eruption, the bigger the earthquakes we see.”

Before the second eruption in August 2022, scientists were not fooled when the earthquakes stopped. They ran tests that showed the volcano was not sleeping. The rock was still moving and the gas was still persisting. Scientists sounded an alarm – and warned that the volcano would likely blow within 24 hours. They were right.

Sigmundsson wants to find out if this reduction in seismicity applies before eruptions at similar volcanoes in Japan, Russia or the United States.

At the moment, Iceland is one of the few places in the world that actively monitors its volcanoes, which it does with an elaborate system of highly specialized instruments.. Elsewhere, a lack of monitoring can sometimes lead to disasters, such as the 2018 outbreak of blue outbursts in Indonesia that killed 400 people. Col geophysicist Matthew Pritchard says Whittaker volcanologists need to do better. About 35% of volcanoes that have erupted in the last 500 years are continuously monitored.

Maintaining instruments to monitor potentially dangerous volcanoes can be expensive.

“So, it’s all a question of priorities. It’s a question of resources,” Pritchard said.

In Iceland, Ed Marshall, a Texas-trained geophysicist at the University of Iceland, used an instrument called an inductively coupled plasma optical emission spectrometer to measure the chemical composition of the lava and determine where it came from.

Some red-hot lava flows out of the volcano while other lava erupts, moving at speeds of up to 10 miles per hour.


Lava flows from a volcano in Iceland

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“The rates at which these different flows can advance and move are different,” Marshall said. “So it’s important to find out because they have different danger potentials.”

Some volcanoes are more difficult to observe, including Grímsvötn in Iceland. Grímsvötn is hidden under a glacier, so seismologist Christine Jonsdottir and her European partners tried something new – burying a coil of fiber optic cable in the ice cap. The cable is thinner than a human hair.

Where regular seismometers barely register a pulse, the fiber optic cable shows Grimsvoten grumbling disconcertingly inside his ice tomb. It has received 100 times more earthquakes. Johnstyre says this could be a game-changer.

“So there’s potential here to be able to understand the volcanoes and the plumbing system,” Jonesttir said. “You know, seeing this high-definition picture that we haven’t seen before.”

Pritchard said there is another solution for better monitoring of volcanoes. He is leading efforts to establish a satellite network that will continuously monitor the world’s most volatile volcanoes. Pritchard said the new gold standard would be to combine ground sensors with satellite imagery to detect eruptions earlier.

Next year, a new satellite will be launched that will use radar waves capable of penetrating dense forest or snow and see deeper underground than ever before, potentially turbocharging volcanologists’ ability to predict eruptions.

In Iceland, Jonsdóttir said he expects more eruptions from the Fagradalsfjal volcano, adding that this time, they know better what to look for.

“Right now, we’re not seeing anything, but we also know it could happen very quickly,” Jonestyr said. “I think we need to be prepared for that, the warning time we have is certainly not many weeks, but maybe just a few days.”

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