They discovered that magma takes an unexpected route under volcanoes

The critical conditions that trigger the volcanic eruption they are still factors of interest to science because they help prevent their effects and protect lives, property and the economy of the surrounding areas. Now researchers from Imperial College London have observed that magma takes an unexpected route under volcanoes, shedding light on the processes behind eruptions.

The results were based on plate boundary data in the region of the Eastern Caribbean. The results help to understand what determines the type and speed of volcanic eruptions, as well as the composition of the magma erupting.

They could also help understand why some volcanoes are more active than others and why volcanic activity changes over time.

The flare phenomenon occurs when two huge tectonic plates they collide, and in doing so, one of them may sink or subduct under the other, plunging into the Earth’s mantle to release water and melt.

As plates rub against each other and molten material rises to form magma, these subduction zones are responsible for some of the most dangerous earthquakes and explosive volcanic eruptions on Earth. However, it is poorly understood how magma forms underground and what controls the exact position of volcanoes above the overlying plate.

Now, this new study published in Science Advances has shown how rising magma, which eventually erupts, doesn’t always take the shortest, most direct path available to reach volcanoes on the surface.

The main author Stephen Hicks, who conducted the work at Imperial College’s Department of Earth Science and Engineering, noted: “Scientific opinions on this highly controversial issue have traditionally split into two factions. Some believe that the plate in subduction It mainly controls the location of volcanoes, and some believe that the plate covering them plays the most important role. But in our study, we show that the interaction of these two driving forces over hundreds of millions of years is key to controlling where eruptions occur today.”

The ace ocean plates in subduction, they act like giant reservoirs, transporting water to the depths of the Earth. These fluids enter the plate through fractures and faults formed during its birth and where they are later deposited beneath Earth’s deep ocean trenches. Water is trapped in fractures and binds to plate minerals.

These, in a state of subduction, are subjected to high pressures and temperatures as they plunge between ten and 100 kilometers deep. These extreme conditions cause trapped water and other volatile elements to be expelled.

These fluids, which melt the hot mantle above, are the key ingredient in the magma that eventually erupts around the arcs of volcanoes at the edges of Earth’s oceans, like the Pacific Ring of Fire. However, the paths that fluids and melting take deep within the Earth, from the subduction plate to the volcanic arc, cannot be directly seen or easily inferred from what is erupting.

To conduct the study, the researchers used data from earthquake to map seismic absorption in 3D, much like a CT scan maps the internal structure of the body in a medical study. When seismic energy from earthquakes passes through different materials, the waves slow down or speed up. Along with these velocity changes, wave energy is also dissipated.

Hot molten rock is particularly attenuating: it absorbs the energy of seismic waves as they pass through it.

So the team collected seismic data from a subduction zone in the eastern Caribbean on volcanic islands in the Lesser Antilles, using ocean floor seismometers to build an accurate 3D image of the subsurface. Unusually, the study found that the zone of greatest seismic attenuation at depth was laterally displaced beneath the volcanoes.

These images led the authors to conclude that once water is expelled from the subduction plate, it is transported downward, causing the mantle to move. melt behind the volcanic front. The cast iron then accumulates at the base of the upper plate before probably being transported into the volcanic arc.

Saskia Goes, co-author of the paper and also a specialist in the Department of Earth Science and Engineering at Imperial, said: “Our understanding of fluid pathways and melting has traditionally focused on subduction zones around the Pacific We decided to study the atlantic subduction because the oceanic plate formed there much more slowly, accompanied by more faults, and subjugate slower than in the Pacific. We think these more extreme conditions would make the flow and melt paths easier to visualize using seismic waves.”

The scientists said their findings provide important clues to the processes behind volcanic eruptions and could help better understand where magma deposits form and replenish beneath volcanoes.

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