Scientists discover new layer of tectonic plates in Earth's mantle

New Delhi: Scientists have discovered what appears to be a new, extra layer of tectonic plates in Earth's mantle. This research may help in explaining the reason behind mysterious series of earthquakes in the Pacific.

Jonny Wu of the University of Houston in the US and colleagues believe that the tectonic plates subducted into the Earth’s mantle millions of years ago.

Tectonic plates are pieces of Earth’s crust and uppermost mantle, together referred to as the lithosphere.

The newly discovered plates slid horizontally inside a water-rich layer of the mantle known as the “transition zone,” which lies 440-660kms below the surface.

These subducted plates appear to travel horizontally for thousands of kilometres at speeds almost as fast as plates move at the surface, researchers said.

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, The Guardian reported.

Researchers suggest that the Vityaz earthquakes could be due to the sliding of a subducted plate within the transition zone. “Basically, 90% of Earth’s deep seismicity (more than 500km deep) occurs at the Tonga area where we have found our long, flat slab,” said Wu.

(With PTI inputs)