The magnetic field that travels ahead of sea level changes is caused by the movement of seawater in a tsunami.
Earth 24 December 2021.
By Leah Crane.
A new study looked at the aftermath of a 2010 earthquake in Chile.
The International Federation of Red Cross and Red Crescent Societies.
Magnetic fields may be able to predict deadly waves. When a lot of seawater moves at the same time, it creates a small magnetic field. The magnetic field can be used to predict the sea level.
We lacked the data to prove that this should be possible for a long time. In order to demonstrate that it is possible, a group of people at Kyoto University in Japan have used data from two of the most destructive earthquakes in history. The magnetic field changes can be used to estimate the sea level change from a wave.
We use pressure gauge on the sea floor to tell us when a wave is moving. The pressure changes only tell us that a wave has passed the sensors. Lin and his team used a set of sensors in the south Pacific Ocean to measure magnetic field and sea level change at the same time as the two tsunamis. They found that the waves were preceded by changes in the water's magnetic field.
Huge underwater landslides and tsunamis may be caused by ooze.
Lin says that pressure sensors respond to the sea level change. The magnetic field arrives earlier than the sea level change.
The magnetic field change arrives about 1 minute before the sea level change, but it depends on the water's depth in the area.
Pressure sensors are often too close to coastlines to give a good warning of a wave.
There are networks of buoys that measure water pressure around the Pacific, but they are usually closer to coast lines than out in the open ocean. They could give data on the waves before they hit.
The magnetic field can be used to predict the height of waves from the ocean.
The journal reference is JGR Solid Earth.
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