Every now and then the Earth’s oceans do something absolutely nightmarish. This can be as simple as reminding humanity that huge predators once roamed their depths or, for example, throwing out a monstrous wave capable of decimating everything in its path. IGN recently covered megashocks, so for now we’ll focus on the latter’s destructive capabilities. As part of a new study, a team of researchers modeled the size of a massive tsunami that swept across the South Pacific Ocean earlier this year. The wave was created when an undersea volcano – called Hunga Tonga-Hunga Ha’apai – erupted with cataclysmic force. Great photos of Earth from Space The sheer violence of the explosion, which took place about 70km north-west of Nuku’alofa – the capital of the Kingdom of Tonga – was enough to trigger the creation of a truly gigantic wave, which proceeded outward towards the coast before hitting the coast. In conducting their study, the scientists used data collected from coastal sea level tide gauges and air pressure records. According to the team, the explosion created powerful atmospheric pressure waves that swept the Earth several times. A combination of the displacement of water from the eruption and these pressure waves both fed into the January event, creating a two-stage tsunami. Coastal areas were first hit by fast-moving waves triggered by atmospheric pressure, which were followed about an hour later by the large wave caused by the displacement of water caused by the explosion.
“We are poorly prepared for volcanic tsunamis”
Computer simulations conducted by the team revealed that the volcano could have displaced an astonishing 6,600 million cubic meters of water, creating a 12 km wide (~39370 ft) wave that had a maximum height of 90 meters (~295000 ft). above sea level. If the maximum height were true, the displacement wave would be almost nine times the height of the wave that hit the Japanese coast in 2011, causing widespread damage and loss of life. Fortunately, in the case of the Hunga Tonga-Hunga Ha’apai eruption, the distance between the volcano and the Tongan coast severely reduced the wave’s destructive potential. Tragically, however, there were still five deaths and according to the World Bank, the devastation caused by this wave and the ash that covered the kingdom in the immediate aftermath caused an estimated US$90.4 million in damages. The authors of the study believe that the Hunga Tonga Ha’apai eruption should serve as a warning to world governments about the risk of future volcanic tsunami events. “This was a huge, unique event and one that highlights that internationally we need to invest in improving systems to detect volcanic tsunamis, as they are currently about 30 years behind the systems we used to monitor for earthquakes,” comments Dr. Mohammad Heidarzadeh, one of the authors of the study from the University of Bath and the Secretary-General of the International Tsunami Committee, “We are poorly prepared for volcanic tsunamis.” Anthony Wood is a freelance science writer for IGN. Article image credit: Shutterstock, Ian Mitchinson
