boom

Tonga volcano spewed ash a whopping 35 miles into the air, setting a new record

Higher than the stratosphere.

Simon Proud / Uni Oxford, RALSpace NCEO / Japan Meteorological Agency

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In January, an undersea volcano violently exploded near Tonga, burying the island nation in ash and stranding residents.

Satellite imagery made it clear that the eruption was among the most powerful in decades.

Simon Proud / NCEO RAL Space / Japan Meteorological Agency

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But it wasn’t until the ash cleared that scientists grasped just how powerful the blast was.

One team recently confirmed that the volcano, called Hunga Tonga-Hunga Ha’apai, shot debris higher into the atmosphere than any other eruption on record.

Simeon Schmauß / JMA / NOAA / KMA

Writing this week in the journal Science, the researchers describe their calculations on the volcano’s plume using satellite data from multiple points of view.

Once a volcanic plume reaches the stratosphere — which was the case with Hunga Tonga — determining its height becomes difficult with standard infrared measurement techniques.

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Simon Proud / NCEO RAL Space / Japan Meteorological Agency

Instead, researchers have to meticulously compare the plume’s height from multiple positions, and use those differences to reconstruct how high the ash cloud soared.

In the case of Hunga Tonga, ash skyrocketed up to 57 kilometers (35.4 miles) into the air.

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That places its plume in the lower mesosphere.

No other volcanic plume on record has breached this layer of the atmosphere.

Simeon Schmauß / JMA

The mesosphere starts at 50 km (about 31 miles) above the ground. Volcanic plumes have only been recorded in the stratosphere and below.

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Previously, the record for the tallest ash plume was set during the eruption of Mount Pinatubo in 1991.

It shot debris over 40 km (24.9 mi) into the air, reaching the high stratosphere.

The researchers note that the abundance of satellite imagery was the major reason why they were able to determine the height of Hunga Tonga’s great blast in the first place.

Simon Proud / NCEO RAL Space / NOAA

“The ability to estimate the height in the way we did ... is only possible now that we have good satellite coverage. It wouldn't have been possible a decade or so ago.”

Simon Proud, lead study author, in a press release.

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The absence of such data surrounding historical blasts could explain why we haven’t seen a plume reach this high before.

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Or it could have been that the Hunga Tonga eruption was abnormally powerful — a scenario that spurs its own questions.