University of Calgary scientists in Canada say they have used measurements of distant earthquakes to learn more about the Earth's core and its formation.

Professor David Eaton and doctoral student Catrina Alexandrakis said knowledge of the composition and the of that core is key to unraveling the source of the Earth's magnetic field and the formation of our planet.

To determine the materials that make up the Earth's core, which is 1,797 miles below the surface, Eaton and Alexandrakis said they measured the seismic wave speed at the top of the core.

"Observation of distant earthquakes is one of the few tools that scientists have to investigate deep parts of the Earth," Alexandrakis said. "This isn't the first time earthquake data has been used, but our research method is the most definitive to date."

Using a digital processing approach, they said they analyzed faint signals produced by 44 earthquakes and were able to measure the sound speed at the top of Earth's core with unprecedented accuracy.

They said their results will help to guide research efforts at laboratories where core composition is studied by simulating extreme pressure and temperature conditions that exist in the Earth's core.

The study appears in the journal Physics of the Earth and Planetary Interiors.