The January 15, 2022, eruption of Hunga Volcano in Tonga continues to interrupt information. In line with a brand new examine, the eruption created a “supercharged” thunderstorm that produced probably the most intense lightning ever recorded. There have been practically 200,000 lightning flashes within the volcanic plume all through the eruption, peaking at greater than 2,600 flashes each minute, the researchers discovered.
When the submarine volcano erupted within the southern Pacific Ocean, it generated a plume of ash, water and magmatic fuel a minimum of 58 kilometers (36 miles) excessive. The towering plume gave scientists helpful details about the dimensions of the eruption, however it additionally obscured the vent from satellite tv for pc view, making it harder to trace adjustments within the eruption because it progressed.
Excessive-resolution lightning information from 4 separate sources — by no means beforehand used all collectively — have now let scientists peer into that plume, teasing out new phases of the eruption’s life cycle and gaining insights into the bizarre climate it created.
“This eruption triggered a supercharged thunderstorm, the likes of which we’ve by no means seen,” mentioned Alexa Van Eaton, a volcanologist at america Geological Survey who led the examine. “These findings reveal a brand new instrument we now have to watch volcanoes on the pace of sunshine and assist the USGS’s function to tell ash hazard advisories to plane.”
The examine was printed in Geophysical Analysis Letters, which publishes high-impact, short-format reviews with quick implications spanning all Earth and area sciences.
The storm developed as a result of the extremely energetic expulsion of magma occurred to blast by way of the shallow ocean, Van Eaton mentioned. Molten rock vaporized the seawater, which rose up into the plume and ultimately fashioned electrifying collisions between volcanic ash, supercooled water and hailstones. The right storm for lightning.
Combining information from sensors that measure mild and radio waves, the scientists tracked lightning flashes and estimated their heights. The eruption produced simply over 192,000 flashes (made up of practically 500,000 electrical pulses), peaking at 2,615 flashes per minute. A few of this lightning reached unprecedented altitudes in Earth’s environment, between 20 to 30 kilometers (12 to 19 miles) excessive.
“With this eruption, we found that volcanic plumes can create the circumstances for lightning far past the realm of meteorological thunderstorms we’ve beforehand noticed,” Van Eaton mentioned. “It seems, volcanic eruptions can create extra excessive lightning than every other type of storm on Earth.”
The lightning supplied perception into not solely the length of the eruption, but additionally its conduct over time.
“The eruption lasted for much longer than the hour or two initially noticed,” Van Eaton mentioned. “The January 15 exercise created volcanic plumes for a minimum of 11 hours. It was actually solely from wanting on the lightning information that we have been capable of pull that out.”
The researchers noticed 4 distinct phases of eruptive exercise, outlined by plume heights and lightning charges as they waxed and waned. The insights gained from linking lightning depth to eruptive exercise can present higher monitoring and nowcasting of aviation-related hazards throughout a big volcanic eruption, together with ash cloud improvement and motion, Van Eaton mentioned. It’s a major problem to get dependable details about volcanic plumes at first of an eruption, particularly for distant, submarine volcanoes. Harnessing all of the long-range observations obtainable, together with lightning, improves early detection to maintain plane and folks out of hurt’s manner.
“It wasn’t simply the lightning depth that drew us in,” Van Eaton mentioned. She and her colleagues have been additionally puzzled by the concentric rings of lightning, centered on the volcano, that expanded and contracted over time. “The dimensions of those lightning rings blew our minds. We’ve by no means seen something like that earlier than, there’s nothing comparable in meteorological storms. Single lightning rings have been noticed, however not multiples, and so they’re tiny by comparability.”
Intense, high-altitude turbulence was once more accountable. The plume injected a lot mass into the higher environment that it despatched out ripples within the volcanic cloud, like dropping pebbles in a pond. The lightning appeared to ‘surf’ these waves and transfer outward as 250-kilometer-wide rings.
As if all that weren’t sufficient to make this eruption fascinating, it represents a mode of volcanism often known as phreatoplinian, which happens when a big quantity of magma erupts by way of water. Beforehand, this eruption fashion was solely recognized from the geological report and had by no means been noticed with fashionable instrumentation. The Hunga eruption modified all that.
“It was like unearthing a dinosaur and seeing it stroll round on 4 legs,” Van Eaton mentioned. “Form of takes your breath away.”