Tonga’s volcanic eruption was caused by an explosion equivalent to ‘five underground nuclear bombs,’ new study reveals
Two years on, new research from the Australian National University (ANU) has revealed the main trigger of one of the largest volcanic eruptions in history, the Hunga Tonga submarine volcano. The study is published in the journal Geophysical Research Letters.
Until now, the cause of this disaster has remained a mystery to most of the scientific community, but a team of ANU student-led seismologists has managed to shed new light on the natural explosion that caused this disaster. .
Student researchers analyzed the noisy but valuable seismic recordings of this climactic event to decipher its mysterious physical mechanisms.
“Our findings confirm that there was an explosion, probably caused by gas-compressed rock, which produced an energy comparable to the five largest underground nuclear explosions carried out by North Korea in 2017. released,” said study co-author and ANU Ph.D. student Jingying Fu said.
“Our models suggest that this event resulted from rock compressed by gas becoming trapped beneath a shallow ocean, like an overheated pressure cooker.
“This will come as a surprise to many, as it was generally thought that such large underwater volcanic eruptions were caused by the interaction of hot magma and cold ocean water.
“For this natural explosion, we used techniques previously developed to study underground explosions.”
Study co-author Dr Tan Son Pham said the explosion pushed water vertically into the atmosphere, triggering tsunamis reaching up to 45 meters on nearby islands.
“The amount of water that rose during the event was enormous. Based on our estimates, there was enough water to fill approximately one million standard Olympic-sized swimming pools,” Dr. Pham said. Ta.
Co-author of the study, Professor Hrvoje Tokarčić from ANU, said: “Using seismic waveform modeling, we observed large upward vertical forces during earthquakes. At first we were perplexed by this, but then the solid Earth I could tell it bounced back,” he added. After the water column rises, it rises upward. ”
“A few weeks ago, we learned how seismology can help explain an unusual series of events in Greenland, including a landslide caused by melting glaciers, a tsunami, and an earthquake that lasted nine days. I saw it being used.
“Hunga Tonga, a relatively short-lived explosive phenomenon observed all over the world, again represents academic curiosity and the best of forensic seismology.”
ANU seismologists say the Tonga eruption is the best instrumentally recorded eruption compared to similar scale eruptions in the recent past.
“This is one of the biggest events of our lifetime. Fortunately, there were multiple ways to record this event, from data from satellite images to seismic sensors that record sound waves and structure.” Hu said.
“Another incident of similar scale occurred in Pinatubo, Philippines, in 1991, but back then surveillance systems were not as sophisticated as they are now.”
ANU seismologists believe that monitoring gas emissions and microseismic activity from volcanic sites can help better prepare for future phenomena.
Further information: Jinyin Hu et al. “Combined seismic source model for the first major event during the 2022 Hunga (Tonga) volcanic eruption”, Geophysical Research Letters (2024). DOI: 10.1029/2024GL109442
Provided by Australian National University
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