An explanation was given for the mysterious tsunami that hit in 2021

Last August, a tsunami from the South Atlantic crossed 10,000 kilometers and hit the coasts of Africa, South America and even Asia. It was the first time since 2004 that a tsunami crossed three different oceans. Scientists managed to find the epicenter and placed it near the South Sandwich Islands, 47 kilometers below the ocean floor.

However, the tsunami was not just the result of a 7.5 magnitude earthquake. Seismological data show that there was a series of five earthquakes. In fact, the third “invisible” earthquake at a depth of only 15 kilometers, was of magnitude 8.2 Richter.

“The third event is important because it was huge and silent. “In the data we usually look at to monitor earthquakes, it was almost invisible,” said the researchers.

By observing seismic data over periods of more than 500 seconds, the scientists detected the presence of a shallow and slow earthquake that we had never seen before. A three-minute earthquake shattered a 200-kilometer stretch, accounting for 70% of all seismic activity recorded.

“It is very difficult to find the second earthquake because it was buried under the first. It is very difficult to detect complex earthquakes like these. And if we do not use the right data we can not see what is hidden inside. With these complex earthquakes, when the earthquake happens we think “oh, it was not that big, we do not need to worry”. And then the tsunami hits and causes great damage. “This study is a perfect example of how we can understand how these events work and how we can detect them faster so that we can warn in time in the future.”

The study was published in Geophysical Research Letters.

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