Tsunamis generate magnetic fields that can be detected a few minutes earlier than changes in sea level. This time, while short, could be enough to save lives in an impending disaster.
The discovery was made by researchers Zhiheng Lin, Hiroaki Toh and Takuto Minami, and it was made in Japan, a country very affected by giant waves — the word “tsunami” has its origins in Japanese. With the new method, they were able to predict wave dimensions in two events: the 2009 tsunami in Samoa and the 2010 tsunami in Chile.
These giant waves are generated by tectonism, the movement of the planet’s tectonic plates. Events are tracked and generate a magnetic field. What is new is that it was possible to detect this field before the changes in sea level.
Typically, tsunami warnings are issued when there are significant changes in the behavior of the oceans. For this, researchers and the civil guard constantly monitor the movement of water. Other data also help in identifying the catastrophe, such as seismology.
Measuring the magnetic field
In this research, scientists simultaneously measured the two parameters, sea level and magnetic field, finding that the second occurs first. “It’s very exciting because in previous studies we didn’t have the observation of sea level change,” says Zhiheng Lin, from the University of Kyoto, in a note in the AGU magazine.
Being able to detect the disaster in advance, even if only a few minutes, is already a great advantage and can save lives. The time gained with the technique depends on the depth of the sea: for 4800 meters, it can reach a minute.
But measuring the magnetic field is such a sensitive technique that even waves of a few centimeters can be found. In addition, the data also allow you to estimate the height of a tsunami.