Earth’s Core. © wikimedia/IsadoraofIbiza
A new study suggests that Earth‘s core may be layered like an onion, which could explain unusual earthquake data.
Scientists have long observed that seismic waves travel through the inner core at varying speeds, depending on their direction. These differences, known as seismic anisotropies, have been difficult to explain.
An international team of researchers, led by scientists from the University of Münster in Germany, believes they have found an answer. Their work was published in the journal Nature Communications.
The team recreated the extreme pressure and heat found deep inside the Earth. Using advanced X-ray equipment at the PETRA III facility in Hamburg, they investigated how iron, mixed with small amounts of silicon and carbon, behaves under these conditions.
The experimental setup at DESY in Hamburg. The cell’s orange colour is created from the light it emits at high temperatures. © Carmen Sanchez-Valle
Their results suggest that when iron contains both carbon and silicon, it can form layered structures. When applied to Earth’s inner core, this layered, onion-like structure could explain the strange patterns seen in seismic waves.
“There have been several hypotheses for the origin of these anisotropies,” states Prof. Carmen Sanchez-Valle from the Institute of Mineralogy at the University of Münster. “Unfortunately, there are very little experimental data on how such LPO might look like in the Earth’s iron core, and there are no data on the LPO of iron–silicon–carbon alloy mixtures. Thus, we set out to study the combined effect of silicon and carbon on the deformation behavior of iron.”
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