There is a lot of water in the world’s most explosive volcano

There’s not much in Kamchatka, a remote peninsula in northeast Russia just across the Bering Sea from Alaska, other than a massive brown bear population and the most explosive volcano. of the world.

Kamchatka’s Shiveluch volcano has experienced more than 40 violent eruptions over the past 10,000 years. The last gigantic explosion occurred in 1964, creating a new crater and covering an area of ​​almost 100 square kilometers with pyroclastic flows. But Shiveluch is currently erupting, as it has been for over 20 years. So why would anyone risk venturing too close?

Researchers at the University of Washington in St. Louis, including Michael Krawczynski, assistant professor of earth and planetary sciences in arts and sciences and graduate student Andrea Goltz, brave the harsh conditions of Kamchatka because understanding what ticks Shiveluch could help scientists understand the global water cycle and gain insight into the plumbing systems of other volcanoes.

In a recent study published in the journal Contributions to mineralogy and petrology, researchers from the Krawczynski laboratory studied small nodules of primitive magma that erupted and preserved among other materials.

“The minerals in these nodules retain the signatures of what happened at the start of magma evolution, deep in the earth’s crust,” said Goltz, the lead author of the article.

The researchers found that the conditions inside Shiveluch include about 10% to 14% water by weight (% by weight). Most volcanoes have less than 1% water. For volcanoes in the subduction zone, the average is typically 4%, rarely exceeding 8% by weight, which is considered superhydrous.

Of particular interest is a mineral called amphibole, which acts as a proxy or fingerprint for high water content at known temperature and pressure. The unique chemistry of the mineral tells researchers how much water is present deep beneath Shiveluch.

“When you convert the chemistry of these two minerals, amphibole and olivine, into temperatures and water content like we do in this article, the results are remarkable in terms of the amount of water and the low temperature that we are recording, “Krawczynski told me.

“The only way to get primitive, pure materials at low temperatures is to add lots and lots of water,” he said. “Adding water to rock has the same effect as salt to ice; you lower the melting point. In this case, there is so much water that the temperature is reduced to a point where the amphiboles can. crystallize.”