Energy unleashed by submarine volcanoes can power a continent

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

Eruptions of deep-sea volcanoes have long been considered relatively uninteresting compared to those on land. While terrestrial volcanoes often cause spectacular eruptions and disperse volcanic ash in the area, deep sea eruptions were thought to only create slow-moving lava flows.

But data collected by remote-controlled vehicles deep in the Northeast Pacific and analyzed by scientists at the University of Leeds has shown a link between the way ash is dispersed during submarine eruptions and the creation of large and powerful columns of heated water. rising from the ocean floor, known as megaplumes.

These megaplumes contain hot water rich in chemicals and act in a similar way to the atmospheric plumes seen from land-based volcanoes, which spread upward and then outward, carrying volcanic ash with them. The size of megaplumes is enormous, with a volume of water equivalent to 40 million Olympic swimming pools. They have been discovered over several submarine volcanoes, but their origin has remained unknown. The results of this new research show that they form rapidly during the eruption of lava.

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

Together they developed a mathematical model showing how ash from these submarine eruptions spreads several kilometers from the volcano. They used the ash pattern deposited by a historic submarine eruption to reconstruct its dynamics. This showed that the amount of energy released and required to transport ash to the observed distances is extremely high – equal to the power used throughout the US.

David Ferguson said, “Most of the volcanic activity on Earth takes place underwater, usually at depths of several miles in the deep ocean, but unlike Earth’s volcanoes, even detecting an eruption on the seafloor is extremely challenging. for scientists to learn about submarine volcanism and its effects on the marine environment. “

The research shows that underwater eruptions cause megaplumes, but the release of energy is so rapid that it cannot be provided by the erupted molten lava alone. Instead, the study concludes that undersea volcanic eruptions are rapidly emptying reservoirs of hot liquids in the Earth’s crust. As the magma makes its way to the sea floor, it floats this hot liquid with it.

Sam Pegler added, “Our work provides evidence that megaplumes are directly related to the eruption of lava and are responsible for the transport of volcanic ash into the deep ocean. It also shows that plumes must have formed in a matter of hours,” thereby releasing a tremendous rate of energy.

David Ferguson added: “It remains extremely difficult to personally observe a submarine eruption, but the development of seabed-based instruments means that data can be streamed live as the activity takes place.

Efforts like this, coupled with constant mapping and sampling of the ocean floor, mean that the volcanic nature of our oceans is slowly being revealed. ”