NASA’s satellite is a true gift: by combining its data with that of ocean buoys and seismographs, scientists can now create much more precise warning systems.
The world of seismology and natural disaster prevention has just experienced a major upheaval. For the first time, researchers have managed to capture a high-resolution image of a spreading tsunami in the middle of the ocean. This technical feat, carried out by NASA’s SWOT satellite following a major earthquake, is not just a simple photo. It reveals a complex energy structure, modifying the physical models used for decades to predict the arrival of destructive waves on our coasts. This is vital information because better understanding the wave at its origin is the key to saving lives as they approach the coastline.
“I view SWOT data as a new pair of glassessaid Angel Ruiz-Angulo, lead author of the study and professor at the University of Iceland . Previously, we could only observe the tsunami at specific points in the vastness of the ocean.he models considered that major waves crossed the ocean as a single block, without fragmenting. The SWOT image, which maps the height of the sea surface over a 120 km wide strip, shows just the opposite: an intertwined network of energy. This phenomenon, called “dispersion”, means that the wave energy is distributed between the leading waves and the tailing waves. By incorporating this effect into forecasts, scientists will be able to better assess the speed, height and impact time of waves as they approach ports and beaches.
The phenomenon was observed following a major magnitude 8.8 earthquake that occurred last July in the Kuril-Kamchatka subduction zone, along the eastern coast of the Russian Far East, according to the study published in the journal The Seismic Record. On the high seas, there was no human or material damage. Tsunamis are only dangerous when approaching the coast, where the decrease in water depth causes the wave to rise dramatically. In the open ocean, a tsunami is only a small ripple (often less than a meter) of very long period, undetectable to the naked eye from a ship.
NASA modeling shows a wave height of 45 centimeters. “A 45-centimeter wave may seem insignificant, but tsunamis are waves that propagate from the seafloor to the ocean surface. What measures only 30 to 60 centimeters in the open sea can turn into a 9 meter wave in the shallower waters of the coast“. The Kuril-Kamchatka area is part of the “Pacific Ring of Fire” and is a region historically prone to major earthquakes and tsunamis. The risk of other tsunamis of this magnitude is therefore permanent.
However, NASA’s satellite provides a true gift: by combining its data with that of ocean buoys and seismographs, planners can now create much more precise warning systems. The goal is not to eliminate risk, but to predict it with unprecedented accuracy. A tsunami generated in the Pacific Ocean, like the Kuril-Kamchatka tsunami, generally has no direct and significant impact on the coasts of Europe.
