UPDATE, 25 January 2022:
The Hunga Tonga Hunga Ha’apai volcano, southeast of Fiji, erupted in spectacular fashion, unleashing tsunamis, shock waves and sending a plume of ash and gas up to 20,000 meters into the atmosphere.
It’s likely to be the largest eruption on the planet in 30 years.
The volcano sits on an uninhabited island about 65 kilometers north of the Tongan capital, Nuku’alofa.
Already preliminary estimates rate the eruption to have a VEI = 5, putting it on par with Vesuvius (79 A.D.) or Mt. St. Helens (1980), but smaller than Pinatubo (1991).
May cool the atmosphere
Satellite images show a plume of ash, steam and gases with a diameter of 5 km rising 20,000 meters into the air, meaning there will be some climatic impact, at least in the southern hemisphere over the first half of 2022.
Sulfur dioxide emitted by eruptions reacts with water to form droplets of sulfuric acid, which then condense to form sulfate aerosols. These aerosols reflect sunlight away from Earth’s surface and act to cool the Earth’s lower atmosphere.
A volcanic explosivity index (VEI) of 5 means over 1 cubic kilometer of ash and material gets thrown into the atmosphere, and the amount reaching the stratosphere is considered as “significant”. An eruption gets a VEI rating of “6” when more than 10 cubic kilometers gets injected into the atmosphere, as was the case with Pinatubo.
The BBC reports the eruption reportedly could be heard as far as New Zealand, 2,300 km away, and heard as “loud thunder sounds” at Fiji more than 800 km away.