The energy unleashed by submarine volcanoes could power a continent

Deep volcanic eruptions in our oceans are capable of extremely strong energy releases at a rate high enough to power the entire United States, according to research published today.

The eruptions caused by deep volcanoes have long been thought to be relatively uninteresting compared to those on land. While terrestrial volcanoes often produce spectacular eruptions, scattering volcanic ash into the environment, deep-sea eruptions were thought to produce only slow-moving lava flows.

But data collected by remotely operated vehicles deep in the Northeast Pacific and analyzed by scientists at the University of Leeds revealed a link between how the ash is dispersed during submarine eruptions and the creation of large and strong columns of heated water rising from the ocean floor, known as megaplumes.

These mega-feathers contain hot water rich in chemicals and act in the same way as atmospheric feathers seen from volcanoes on land, spreading first upwards and then outwards, carrying with them volcanic ash. The size of the megaplums is huge, with volumes of water equivalent to forty million Olympic pools. They were detected above various submarine volcanoes, but their origin remained unknown. The results of this new research show that it forms rapidly during the lava eruption.

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

Together they developed a mathematical model that shows how the ash from these submarine eruptions spreads a few kilometers from the volcano. They used the ash model deposited by a historic submarine eruption to reconstruct their dynamics. This showed that the rate of energy released and needed to transport the ash at the observed distances is extremely high – equivalent to the power used by the entire US.

David Ferguson said: “Most of the Earth’s volcanic activity takes place underwater, especially at depths of a few kilometers in the deep ocean, but unlike terrestrial volcanoes, even detecting an eruption on the seabed is extremely difficult. Consequently “There is still a long way to go for scientists to learn about underwater volcanism and its effects on the marine environment.”

Research shows that submarine eruptions cause the formation of megaplumes, but the release of energy is so rapid that it cannot be fed only from the erupted molten lava. Instead, the research concludes that submarine volcanic eruptions lead to the rapid emptying of hot fluid reservoirs in the earth’s crust. As the magma forces its way up to the bottom of the sea, it carries this hot fluid with it.

Sam Pegler added: “Our work provides evidence that megaplums are directly related to the lava eruption and are responsible for transporting volcanic ash into the deep ocean. It also shows that the feathers must have formed within a few hours, creating a huge rate of energy release.

David Ferguson adds: “Observing a submarine eruption in person remains extremely difficult, but the development of seabed-based instruments means that data can be transmitted live as activity occurs.

Efforts like these, consistent with continuous mapping and ocean floor sampling, mean that the volcanic character of our oceans is easy to discover. ”