Using satellite images, Oxford University researchers confirmed that
January 15, 2022 there was a strong eruptionunderwater volcano Hunga-Tonga-Hunga-Hapai, located on the Tongan archipelago in the South Pacific Ocean. The explosion was one of the most powerful in the history of observations, it sent shock waves around the world and caused a devastating tsunami that left thousands of people homeless. A huge column of ash and water was thrown into the atmosphere, but until now, scientists have not had an accurate way to measure its height.
Usually the height of a volcanic plume can beestimate by measuring the temperature recorded at the summit by infrared satellites and comparing it with a conventional vertical temperature profile. But if the eruption is so large that the plume penetrates the stratosphere, this method becomes ambiguous as temperatures begin to rise again with height due to the ozone layer.
To solve this problem, the researchers used a new method based on the "parallax effect". This is the apparent difference in the position of an object when viewed from multiple angles.
Volcano Tonga
The location of Tonga Volcano is covered by threegeostationary meteorological satellites, so the researchers were able to apply the “parallax effect” to aerial imagery. During the eruption itself, satellites took pictures every 10 minutes, which made it possible to record rapid changes in the plume's trajectory.
The results showed that the plume heightreached a maximum of 57 km. This is significantly more than previous record holders: the 1991 eruption of Mount Pinatubo in the Philippines (40 km at its highest point) and the eruption of El Chichon in Mexico in 1982 (31 km). The volcano ejected material into the stratosphere and mesosphere.
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