This animation reveals a stereo view of the Tonga eruption plume as it increased, developed, and dispersed over the course of 13 hours on January 15, 2022. According to these observations, the initial blast rapidly increased from the ocean surface to 58 kilometers in about 30 minutes. Recordings of the eruption of the Hunga Tonga volcano by the stations of the international seismological network. The very first burst corresponds to the recording of surface seismic waves (P- and Rayleigh waves), while the later-arriving waves are due to sound waves taking a trip through the air (air waves).
This animation reveals a stereo view of the Tonga eruption plume as it increased, developed, and distributed over the course of 13 hours on January 15, 2022. The animation was constructed from infrared observations got every 10 minutes by GOES-17 and Himawari-8. According to these observations, the initial blast rapidly rose from the ocean surface to 58 kilometers in about 30 minutes. Soon afterward, a secondary pulse increased above 50 kilometers (31 miles), then separated into three pieces. Credit: NASA Earth Observatory
Seismic Algorithm Reveals the Magnitude of the January 2022 Tonga Islands Eruption
On January 15, 2022, the eruption of a submarine volcano in the Tonga island chain destroyed 90% of the uninhabited island of Hunga Tonga Haapai and formed an ash plume half the size of France. It also produced an atmospheric shock wave that circled around the Earth several times, and, more classically, seismic waves recorded by monitoring stations all over the world.
By evaluating the seismic waves, two CNRS researchers [1] were able to develop an algorithm that can spot and locate a volcanic eruption in near real-time and, using equations that explain explosive eruptions, evaluate its size. Previously, such an assessment required fieldwork and took numerous weeks or months, because it was necessary to estimate the volume of ash and lava produced.
Recordings of the eruption of the Hunga Tonga volcano by the stations of the international seismological network. The first burst corresponds to the recording of surface area seismic waves (P- and Rayleigh waves), while the later-arriving waves are because of sound waves taking a trip through the air (air waves). Credit: © Piero Poli
The authors show that the Hunga Tonga eruption ejected a volume of around 10 km3, making it the biggest explosive eruption of the twenty-first century, equivalent in strength to that of the destructive eruption of Pinatubo (Philippines) in 1991.
Recommendation: “Rapid characterization of large volcanic eruptions: determining the impulse of the Hunga Tonga explosion from teleseismic waves” 20 April 2022, Geophysical Research Letters.DOI: 10.1029/ 2022GL098123.
Working at the Institut des Sciences de la Terre (CNRS/Universit é Grenoble Alpes/IRD/Universit é Savoie Mont Blanc).
This approach ought to make it simpler to study big explosive eruptions in remote areas. Its reactivity, of the order of an hour, could help to forecast the areas most likely to be affected by ash, which can interfere with human activities both on the ground and in the air.
The research study will be published today (April 20, 2022) in Geophysical Research Letters, received funding from two ERC grants, Monifaults (Starting grant) and Seismaze (Advanced grant).
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