New database maps and classifies the dangers of glacierized volcanoes

Fire and Ice: New Database Maps and Classifies the Dangers of Glacierized Volcanoes
Maps of the Smithsonian Global Volcanism Database and the Randolph Glacier Inventory. Source: Benjamin Edwards, et al. “Global Mapping of Future Volcanism”

Destructive volcanic mudflows, huge clouds of volcanic ash that ground flights, and catastrophic floods when natural glacial lake dams fail—these are all examples of the dramatic interactions between volcanoes and glaciers. To help others study, and hopefully predict, dangerous glaciovolcanic activity, researchers have created a new database that combines existing global data.

This study is a valuable resource that could aid further research and also help determine the world’s most dangerous glacierized volcanoes. The study was conducted by Benjamin Edwards, a volcanologist at Dickinson College, William Kochtitzky, a student at Dickinson when the study was conducted, and Sarah Battersby, a research scientist at Tableau Software. Led by Edwards, the volcano expert of the group, the researchers first compiled data on the location of volcanoes and their eruption histories. Kochtitzky, interested in glaciology and mapping, brought together data on glacial ice location, thickness, and volume. To determine the very real dangers this combination could pose, they determined how many people live near each glacierized volcano.

Glacierized volcanoes pose unique risks to human populations. When the red hot lava meets the dense layers of ice, a huge amount of energy is released which can then lead to out of control mudflows, clouds of ash and steam, and glacial outburst floods.

Edwards described the impact that glaciers can have on the frequency and intensity of volcanic mudflows, also known as lahars: “A lahar is a mudflow where most of the material is made out of volcanic rocks and ash. You can have lahars in a variety of settings, but they need water. If you’ve got a volcano with ice on it, there’s a good chance that when the volcano erupts, some of the ice is going to melt. Then you have water and volcanic debris which turns into a volcanic mudflow.”

Glacial lake outburst floods or jökulhlaups occur when a glacial-lake is filled with melting glacial water and the volume of water exceeds what the lake is able to hold. A rapid and catastrophic flood occurs when this intense volume causes a glacial dam to break. When a glacier is subjected to the heat of a volcano, it could melt more rapidly and increase the likelihood of a jökulhlaup.

Human populations can be profoundly impacted by glacier-volcano interactions. To live below a glacier is to face the possibility of a devastating flood or a sudden decline in water supply. “There are 160 million people that live within 100 kilometers of a glacierized volcano,” Kochtitzy told GlacierHub.

Using the database that they created, the research team was able to classify volcanoes based on their potential to harm human populations. “We ranked volcanoes based on how many eruptions they’ve had, how many people live near them, and the volume of ice,” explained Kochtitzky.

While these rankings are not timed predictions of volcanic eruptions and their exact danger, they do provide valuable classifications that

Read more

Volcanoes Spew Sulfur Into Atmosphere of Jupiter’s Moon Io

Jupiter’s moon Io is a dramatic place — even though it’s just 1,131 miles across, or just a bit bigger than Earth’s moon, it hosts over 400 active volcanoes, some of which are as large as 124 miles across. These volcanoes spew out sulfur gases that freeze on the moon’s chilly surface and give it its distinctive yellow and orange color.

Another odd feature about Io is that it has an atmosphere, albeit an extremely thin one. At a billion times thinner than Earth’s atmosphere, it’s barely there, but it does exist and is composed mostly of sulfur from the volcanoes. But researchers weren’t sure about how exactly this atmosphere formed, so recent research has used Earth-based telescopes to examine this puzzle.

“It was not known which process drives the dynamics in Io’s atmosphere,” lead author Imke de Pater of the University of California, Berkeley, explained in a statement. “Is it volcanic activity, or gas that sublimates from the icy surface when Io is in sunlight? What we show is that, actually, volcanoes do have a large impact on the atmosphere.”

Composite image showing Jupiter's moon Io in radio (ALMA), and optical light (Voyager 1 and Galileo). The ALMA images of Io show for the first time plumes of sulfur dioxide (in yellow) rise up from its volcanoes. Jupiter is visible in the background (Cassini image).
Composite image showing Jupiter’s moon Io in radio (ALMA), and optical light (Voyager 1 and Galileo). The ALMA images of Io show for the first time plumes of sulfur dioxide (in yellow) rise up from its volcanoes. Jupiter is visible in the background (Cassini image). ALMA (ESO/NAOJ/NRAO), I. de Pater et al.; NRAO/AUI NSF, S. Dagnello; NASA/JPL/Space Science Institute

The researchers took radio images from the Atacama Large Millimeter/submillimeter Array (ALMA) when Io was moving in and out of the shadow of Jupiter. This change in temperature allowed them to see different states of the sulfur in the atmosphere.

“When Io passes into Jupiter’s shadow, and is out of direct sunlight, it is too cold for sulfur dioxide gas, and it condenses onto Io’s surface,” co-author Statia Luszcz-Cook from Columbia University said. “During that time we can only see volcanically-sourced sulfur dioxide. We can therefore see exactly how much of the atmosphere is impacted by volcanic activity.”

The readings showed that between 30% and 50% of the sulfur in the atmosphere comes directly from the volcanoes. And there was an unexpected bonus finding as well: Another gas, potassium chloride, was also spotted coming from the volcanoes. This gas was only spotted in certain regions, suggesting that different magma reservoirs feed different volcanoes on the surface.

Editors’ Recommendations

Source Article

Read more