A new study conducted by researchers from the Australian national University (ANU) can help us understand how our planet was formed. Associate Professor, Hrvoje, Tkalcic and Dr. Thanh-Pham Sleep sure that proved that the Earth’s inner core is solid. They found a way to detect shear waves (J-waves) in the inner core such waves can only travel through solid objects.
“We found that the inner core is actually solid, but softer than previously thought,” says Tkalcic.
“If it turns out that our results are correct — the inner core will have some elastic properties resembling the properties of gold and platinum. The inner core is a time capsule If we understand her, we understand, as emerged and evolved planet.”
Located in the center of the Earth?
Internal shear waves are so small and weak that they cannot be observed directly. Their discovery is considered the “Holy Grail” of seismology of the world, because scientists first predicted the existence of a solid inner core in 30-40 years of the last century.
So you have to be resourceful to find them.
Their method correlated wave field looking for similarities between the signals from both receivers after a major earthquake, not direct proceeds of the waves. This technique was used to measure the thickness of ice in Antarctica.
“We reject the first three hours of the seismograms and look at what is happening between three and ten hours after the earthquake. We want to get rid of large signals. Using a global network of stations we take every single pair of receivers and each individual a big earthquake — a lot of combinations — and measure the similarity between seismograms. This cross-correlation, or measurement of similarity. On these similarities, we create a global correlogram — a replica of the earth.”
The results showed that the Earth’s inner core — the center of the planet — really solid, but many variables are still unknown — for example, temperature.
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Confirmed: the Earth’s inner core solid
Ilya Hel