The eruption of Tonga’s Hunga Volcano on January 15, 2022, lasted at least 11 hours and produced a record-breaking amount of lightning. The information gathered about the eruption can be used to better monitor aviation-related hazards arising from these sorts of eruptions.
The Hunga Volcano in the southern Pacific Ocean is a submarine volcano. The volcano began rumbling in December 2021, with its explosive activity ramping up on 13 January 2022, culminating in a plume of ash, water and magmatic gas being shot at least 36 miles (58 km) into the mesosphere two days later.
While, at the time, the giant plume they observed gave researchers some idea about the scale of the eruption, it wasn’t until they viewed high-resolution data from four separate sources that they truly understood the eruption’s chronology and the effects it produced.
“This eruption triggered a supercharged thunderstorm, the likes of which we’ve never seen,” said Alexa Van Eaton, lead author of the study. “These findings demonstrate a new tool we have to monitor volcanoes at the speed of light and help the USGS’s [United States Geological Society’s] role to inform ash hazard advisories to aircraft.”
Relying on data from sensors that measure light and radio waves, the researchers tracked lightning flashes and estimated their heights. They found that Hunga’s eruption created just over 192,000 flashes made up of almost 500,000 electrical pulses. Flashes peaked at 2,615 per minute and reached altitudes between 12 and 19 miles (20 and 30 km) high, something that’s never been seen before.
“With this eruption, we discovered that volcanic plumes can create the conditions for lightning far beyond the realm of meteorological thunderstorms we’ve previously observed,” Van Eaton said. “It turns out, volcanic eruptions can create more extreme lightning than any other kind of storm on Earth.”
The volcano’s plume pushed so much mass into the mesosphere that it produced waves in the volcanic cloud, much like the ripples created in a pond when a stone is dropped into it. The lightning was seen to ‘surf’ these waves, moving outward in huge 150-mile (250-km) rings.
“It wasn’t just the lightning intensity that drew us in,” said Van Eaton. “The scale of these lightning rings blew our minds. We’ve never seen anything like that before, there’s nothing comparable in meteorological storms. Single lightning rings have been observed, but not multiples, and they’re tiny by comparison.”
It can be challenging to obtain reliable information about volcanic plumes at the beginning of a volcanic eruption, especially from submarine volcanoes. The insights gained from Hunga’s eruption can be used to better monitor aviation-related hazards during a large volcanic eruption in the future, the researchers say.
It’s the first time a large volume of magma erupting through water, known as a phreatoplinian eruption, has been observed using modern instruments. Until now, scientists have only seen evidence of phreatoplinian eruptions in geological records.
“It was like unearthing a dinosaur and seeing it walk around on four legs,” Van Eaton said. “Sort of takes your breath away.”
The study was published in the journal Geophysical Research Letters, and the below video, produced by the American Geophysical Union (AGU), shows the meteorological effects produced by Hunga’s eruption.
Source: AGU
