Energy unleashed by submarine volcanoes could drive a continent

Volcanic eruptions deep in our oceans are capable of extremely powerful energy releases, at a rate high enough to propel the entire United States, according to research published today.

Eruptions of deep-sea volcanoes are expected to be relatively uninteresting compared to those on land. While terrestrial volcanoes often produce spectacular eruptions and distribute volcanic ash in the area, deep marine eruptions were thought to cause only slow-moving lava flows.

But data collected by remote-controlled vehicles deep in the North East Pacific and analyzed by scientists at the University of Leeds showed a link between the distribution of ash during the eruption of the submarine and the creation of large and powerful columns with heated water rising from the seabed, known as megaplumes.

These mega-plumes contain hot chemically rich water and work in the same way as the atmospheric plumes seen from land volcanoes, which first spread upwards and then outwards and carry volcanic ash with them. The size of megaplumes is enormous, with the amount of water equal to forty million swimming pools in the Olympic Size. They have been detected above various subsea volcanoes, but their origin remains unknown. The results of this new research show that it forms rapidly during the eruption of lava.

The research was conducted by Sam Pegler of the School of Mathematics and David Ferguson of the School of Earth and Environment and is published in the journal today. Nature communication.

Together they developed a mathematical model that shows how some of these submarine eruptions spread several kilometers from the volcano. They used the aspen pattern laid down by a historic submarine eruption to reconstruct its dynamics. It has shown that the rate of energy released and required to transport ash to the observed distances is extremely high – equivalent to the power used throughout the US.

David Ferguson said: “Most of the Earth’s volcanic activity takes place underwater, mostly at a depth of a few kilometers in the deep ocean, but unlike terrestrial volcanoes, it is even extremely challenging to notice that an eruption on the seabed, much for scientists to learn about underwater volcanism and its effects on the marine environment.

The research shows that submarine eruptions cause megaplume to form, but the release of energy is so fast that it cannot be supplied by the erupting molten lava alone. Instead, the conclusion is that volcanic eruptions under water lead to the rapid emptying of the storage dams of hot liquids in the earth’s crust. As the magma forces itself upwards towards the seabed, it drives the hot liquid with it.

Sam Pegler added: “Our work provides evidence that megaplume is directly linked to the eruption of lava and is responsible for the transport of volcanic ash into the deep ocean. It also shows that plumes must have formed within a few hours, which ‘ a tremendous rate of energy release.

David Ferguson adds: ‘The observation of a submarine eruption is still very difficult, but the development of instruments based on the seabed could mean that data can be streamed directly as the activity takes place.

Efforts like these, in conjunction with continued mapping and sampling of the ocean floor, mean that the volcanic character of our oceans is slowly coming to light. ‘