The Tonga eruption was recognized as the largest volcanic eruption of the XXI century

The last eruption of the Tonga volcano was recognized as the largest explosive eruption of the 21st century by French volcanologists from the University of Grenoble-Alpes, after a comprehensive analysis of the collected data. They put it on par with the most powerful eruptions ever recorded in Earth’s history. An article about this was published in the journal. Geophysical Research Letters.

During this explosion, materials with a volume of about 10 km were ejected.³This, among other things, created an atmospheric shock wave that circled the planet several times, creating an ash cloud half the size of France. This eruption is equivalent to the catastrophic eruption of Mount Pinatubo in the Philippines in June 1991, which killed at least 875 people.

To determine the scale of the explosion, Piero Poli and Nikolai Shapiro used a specially developed algorithm that significantly reduced the amount of fieldwork and direct measurements. The rating on the volcanic activity scale VEI – Volcanic Explosiveness Index – a volcanic eruption is therefore set to 6, and such an eruption is expected to occur no more than once every 50-100 years. The largest known eruptions on the VEI scale are assigned the eighth level – such catastrophes happen about once every 50 thousand years, they can produce up to 1000 km³ emissions. No such eruption has been recorded in the last tens of thousands of years.

The eruption of the Hunga-Tonga-Hunga-Ha’apai volcano in January 2022 – that’s its full name – destroyed 90% of the uninhabited island of Hunga-Tonga-Hunga-Ha’apai in the Tonga archipelago and appeared only after 2015. Another weaker eruption, when the space between the islands of Hunga-Tonga and Hunga-Haapai was filled by a large volcanic caldera rising from the seafloor.

The existence of a new algorithm for calculating the strength of explosions could be particularly useful when explosions occur in remote areas where the equipment for direct measurements is not available. An extensive network of hundreds of seismic monitoring stations around the world can instantly pick up the echo from the start of the explosion, even from great distances, these seismic wave recordings are then used to calculate the scale of the explosion. Also, given enough data, in just one hour, the algorithm can estimate the size of the resulting ash cloud while assessing how that cloud might affect the environment.