The eruption of the Tonga volcano caused the largest lightning strikes in history.

The mixture of ash, water, and igneous gases formed a 58-kilometer plume of smoke in the middle of the Pacific, resulting in the emergence of an unprecedented electrical device. “The eruption unleashed an extremely powerful storm that we’ve never seen before,” says Alexa Van Eaton, a volcanologist with the United States Geological Survey.

Combining data from four different sources used to monitor thunderstorms, For the first time, scientists were able to observe what was happening inside that column.. In turn, it’s a possibility that allows them to find information about new stages of the explosion’s life cycle and the changes it created in the climate.

Findings collected by the journal Geophysical Research LettersNot only is it a shock to the knowledge of volcanoes, it also shows that this new tool for monitoring their lightning contributes to “monitoring their behavior in real time”. This means it can be used to better monitor the development and movement of the ash plume, informing emergency teams and security forces, and better control of aviation in the area.

The Tongan volcano spewed its magma with an energy of 5 to 30 megatons. This figure is equivalent to the explosion of hundreds of Hiroshima bombs. at the same time. But being under the sea was very different from what could happen on land.

The paper’s lead author, Van Eaton, said the storm developed because the high-energy magma eruption was pushing through the shallow ocean. The molten rock evaporated the seawater and rose in a gigantic smoke, and finally exciting collisions between volcanic ash, supercooled water and hail. So, a perfect storm for lightning.

Up to 30 kilometers altitude

It was. Lightning followed one another wildly in that dull cloud. Every minute, 2,600 discharges circulated through the smoke column. A few days later, The rays produced by the volcano were more than 192,000. (divided into approximately 500,000 electrical pulses). And they were not only very, but also very powerful, reaching an altitude of 30 kilometers, that is, the stratosphere.

“With this eruption, we discovered that volcanic pillars can create the right conditions for producing lightning that is much more energetic than those from storms as we know it,” insists Van Eaton, and confirms that after making this finding, there were “explosions.” Volcanic storms can produce more extreme lightning than any other type of storm on Earth.”

Thanks to the detailed analysis of the rays occurring inside the plume, the researchers were able to determine the actual duration of the explosion. “The eruption lasted much longer than initially observed,” says Van Eaton. Specifically, the eruption event this volcano suffered on January 15 “created volcanic plumes for at least 11 hours.”

In addition, The rays revealed the behavior of the volcano during different eruption phases. In fact, the researchers were able to identify four different phases of blast activity, depending on the heights of the plumes (ascending and descending convective currents) and lightning speed.

However, the intensity of lightning wasn’t the only thing that drew the research team to the area. Van Eaton and his colleagues were also surprised. by concentric ray rings formed in the center of the volcano. “The scale of the sighting of these lightning rings blew our minds. We’ve never seen anything like it before and we can’t compare it to any meteorological storm,” explains Van Eaton. observed in storms, but they are usually smaller and appear alone.

First freatoplinian eruption

Intense turbulence at high altitude was responsible for this rare event. The smoke injected so much mass into the upper atmosphere that it sent ripples through the volcanic cloud like pebbles falling into a pond. Lightning seemed to “surf” on these waves and move outward in rings 250 kilometers wide.

As if all that wasn’t enough, Tonga volcano’s first eruption nature, This is formed by the eruption of large volumes of magma into the water. This phenomenon has been recorded thanks to modern instrumentation. Until now, such an eruption could only be studied through the geological record. But Tonga Hunga changed it. “It was like picking a dinosaur off the ground and watching it walk,” says Van Eaton.

Reference work: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL102341

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Contact details of the environment department: crisisclimatica@prensaiberica.es