Scientists discover new tectonic plates in Earth’s mantle
A newly discovered layer of tectonic plates within the Earth’s mantle could explain a mysterious series of earthquakes in the Pacific, the Guardian reported.
On Tuesday, Jonny Wu of the University of Houston presented preliminary evidence of possible tectonics plate within the mantle to a joint conference of the Japan Geoscience Union and the American Geophysical Union in Tokyo.
The plate movements may explain a mysterious series of very deep, large earthquakes known as the Vityaz earthquakes, which originated in the mantle between Fiji and Australia. Just as in conventional tectonic plates at Earth’s surface, the bends and breaks in these subducted plates can generate earthquakes.
“Basically, 90% of Earth’s deep seismicity occurs at the Tonga area where we’ve found our long, flat slab,” Wu told the Guardian.
The discovery has been made possible by recent advances in seismology allowing scientists to generate pictures of Earth’s interior using vibrations from natural earthquakes.
Wu compares the new pictures to images from the Hubble space telescope.
“Think of Hubble. We look out, and the further we look out the more things we discover, not just about the universe – we’re actually looking back in time,” he told the newspaper. “And this new seismology is like turning the Hubble to look into the Earth, because as we look deeper and get clearer images, we can see what the Earth might have looked like further and further back in time.”
The seismological pictures can be used to locate tectonic plates lurking within the mantle and then reconstruct the configuration on Earth’s surface millions of years ago.
“We’re discovering lost oceans that we didn’t even know existed,” said Wu, who with colleagues recently discovered an 8,000 km wide East Asian Sea which existed between the Pacific and Indian oceans 52 million years ago, and is now buried 500-1000 km deep in the mantle under east Asia.