New research reveals more about the scale of January's eruption, as researchers call for better preparedness

The initial tsunami cloud created by the eruption of the Hunga Tonga Ha’apai submarine volcano in Tonga in January 2022 reached 90 meters in height, about nine times higher than that of the very destructive tsunami of 2011 in Japan, according to new research.

An international research team says the eruption should serve as a warning sign for groups organizations seeking to protect people from similar events in the future, claiming that volcanic tsunami detection and monitoring systems have “30 years behind” comparable tools used to detect earthquake-based events.

Dr. Mohammad Heidarzadeh, Secretary General of the International Tsunami Commission and Master of lectures at the Department of Architecture and Civil Engineering of the University of Tub, is the author research alongside colleagues based in Japan, New Zealand, the UK and Croatia.

For comparison, the largest tsunami waves due to earthquakes before the Tonga event were recorded following the Tōhoku earthquake near Japan in 2011 and the Chilean earthquake in 1960, reaching 10 meters of initial height. These were more destructive as they occurred closer to land, with larger waves.

According to Dr. Heidarzadeh, the Tonga tsunami should serve as a warning sign for better preparation and better understanding of results in and signs of tsunamis caused by volcanic eruptions. He says: “The Tongan tsunami tragically killed five people and caused widespread destruction, but its effects could have been even greater had the volcano been located closer to human communities. The volcano is located about 70 km from the Tongan capital Nuku’alofa – – this distance has considerably minimized its destructive power.

“This was a gigantic and distinctive event that highlights that at the intercontinental level, we must invest in improving volcanic tsunami detection systems, as these currently have approximately 30 years behind the systems we used to monitor earthquakes. We are underprepared for volcanic tsunamis. ”

The research was conducted by analyzing ocean observational data records of atmospheric pressure changes and sea level oscillations, in combination with validated computer simulations with real-world data.

The research team found that the tsunami was one of a kind car or truck the waves were created not only by the water displaced by the eruption of the volcano, but also by huge atmospheric pressure waves, which repeatedly circled the world. This “dual mechanism” created a two-part tsunami – where initial ocean waves created by atmospheric pressure waves were followed more than an hour later by a second wave created by moving water from the eruption.

This combination means that the tsunami warning centers did not detect the obscure initial automobile they are programmed to detect tsunamis based on water movements rather than atmospheric pressure waves.

The research team also found that the January event was among very few tsunamis powerful enough to circumnavigate the globe – it has been recorded in all the oceans and great seas of the world, from Japan and the west coast of the United States in the North Pacific Ocean to the coasts. within the Mediterranean Sea.

The article, co-authored by colleagues from New Zealand’s GNS Science, Association for the Development of Earthquake Prediction of land in Japan, the University of Split in Croatia and Brunel University in London, was published this week in Ocean Engineering.

Dr. Aditya Gusman, modeller of tsunamis to the New Zealand-based geoscientific company, states: “The eruptions of the Anak Krakatau volcano in 2018 and the Hunga Tonga-Hunga Ha’apai volcanoes in 2022 have clearly shown us that the coastal areas surrounding the volcanic islands are at risk of being hit by destructive tsunamis. Although it may be preferable to have low-lying coastal areas completely clear of residential buildings, such a policy may not be practical for some locations as volcanic tsunamis may be considered infrequent events.

Co-author Dr. Jadranka Šepić, University of Break up, Croatia, adds : “What is vital is to have effective warning systems, which include both real-time warnings and education on what to do in the event of a tsunami or warning – – such systems save lives. Also, in volcanic areas, monitoring of volcanic activity should be organized, and further research into volcanic eruptions and risk areas is always a good idea.

Separate research by Tub University atmospheric physicist Dr Corwin Wright, published in June, found that the Tonga eruption triggered atmospheric gravity waves that reached the edges of space .

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