There's a Change Happening to Earth's Outer Core, as Revealed by Seismic Wave Data

The majority of our knowledge about the center of our planet comes from the study of earthquakes. Rocks and metal can be found below Earth's surface.

Changes that are happening in Earth's outer core, as well as the swirling layer of liquid iron and nickel between the mantle and the inner core, have been revealed by a new study.

Our planet's magnetic field is influenced by the outer core and iron contained in it, which in turn protects us from space and solar radiation that would otherwise make life impossible.

Understanding the evolution of the outer core is crucial. When waves from the later event traveled through the same region of the outer core as the earlier ones, they traveled around one second quicker.

The path of the wave has changed so it can go faster now. The material that was there in the past is no longer there.

The material is new and lighter. The density in the region where these light elements are located will be changed by their movement upward.

The types of waves analyzed here are shear waves, which pass through the mantle as shear waves, then into the outer core as compressional waves, then out the other side and back through the mantle again as more shear waves. It is possible to reveal the timing of that travel.

The Kermadec Islands in the South Pacific Ocean were the location of the first and second earthquakes.

How seismic waves travel through the outer core. (Ying Zhou)

The electrical currents created by the molten iron of Earth's outer core are what control the magnetic field around us. The relationship between the outer core and Earth's magnetic field is not fully understood.

The north geomagnetic pole is moving at a speed of about 50 kilometers per year. It is moving away from Canada. The field is not always the same. The thing is changing.

There is no direct evidence that the outer core is changing. We haven't seen it yet.

The study could provide useful insights into how the outer core is changing. The more we know, the better.

Zhou suggests that lighter elements have been released from the outer core since 1997. It corresponds to a density reduction of about 2% and a speed of about 25 miles per hour.

The Global Seismographic Network has over 150 stations around the world. We can make sure that as much data as possible is kept about earthquakes, even though we can't control their location or timing.

Zhou says they can see it now. If we can see it from the waves, we could set up stations to watch it.

The research was published in a journal.