Over 100 years ago, a ship encountered a water bubble “the size of the US Capitol” – now we know what happened.
In 1908, a US Navy ship was sailing north of the Fox Islands. In that area of the Aleutians, fog, bad weather and reefs make it not the best place to sail. And so the sailors who entered the frozen waters of Alaska were prepared for anything.
Or for almost everything. Because there is nothing in the ocean that prepares you to see how the sea, in front of your eyes, begins to “swell in the form of a gigantic dome as big as that of the Washington Capitol ”Those were his exact words.
“The dome contracted and grew back until it finally exploded in great clouds of smoke and steam.” It was then that “spellbound spectators began to fear that they would be involved in a terrible cataclysm.” Luckily, it was not like that and his story reached us as a strange tale of frightened sailors.
Now we know what happened.
A volcano in Alaska
Many years later, in 2017, the Bogoslof erupted. For nine months, the volcano interrupted air traffic in the area due to the huge clouds of ash and steam that it expelled into the atmosphere and that reached up to 11 kilometers above sea level. In those months, something else happened. The Alaska Volcano Observatory microphones picked up a strange, low and slow melody that was repeated more than 250 times.
It is not usual. “Instead of happening very fast and with high frequencies as is typical in explosive eruptions, what we found were ** signals of really low frequencies ** and some of them had periods of up to 10 seconds”, explained John Lyons, geophysicist of the AVO.
For months, the sounds of the volcano had the scientific community intrigued. Until one day, a colleague of Lyons realized that, curiously, Bogoslof volcano was north of the Fox Islands. Could both things be related?
Lyons and his team created models of overpressurized gas bubbles in a frigid water context and cold air. For this, they were inspired by the studies of magmatic bubbles that have been documented in the Stromboli volcano in Italy. Those bubbles were much smaller, but they had characteristics in common. The question is whether a similar phenomenon at a larger size could result in what the microphones were detecting.
And the results, just published in Nature Geoscience, indicate that it is. According to your data, submerged volcanic explosions can produce bubbles the size of the Capitol dome or even bigger. Estimates say that bubbles from the 2017 Bogoslof eruption ranged from 100 to 440 meters in diameter.
The researchers acknowledge that it is difficult to imagine gas bubbles of that size, but the data is stubborn and the models robust. In addition, there are a couple more eruptions that also fit this idea: that of the Myojin volcano in Japan in 1952-53 and that of the Karymsky volcano in Russia in 1996. We will have to wait for the next eruption and send teams to observe live, but, for now, more than a century later it seems that We have found an answer to the mystery of the north of the FOx.