Pacific Plate Being Torn Apart From Japan To New Zealand, Finds Study

Earth's rigid outer shell is divided into a dozen large tectonic plates, and a major one - the Pacific plate - is being pulled apart. The discovery has been made by researchers from University of Toronto and is shedding new light on the century-old model of plate tectonics. The team found that the Pacific plate is scored by large undersea faults that are pulling it apart. The research has been published in the journal Geophysical Research Letters and talks about the enormous forces that are tugging away the plates.

The undersea faults are hundreds of kilometres long and thousands of metres deep.

"We knew that geological deformations like faults happen on the continental plate interiors far from plate boundaries. But we didn't know the same thing was happening to ocean plates," Erkan Gun, a post-doctoral researcher in the department of Earth Sciences in the Faculty of Arts & Sciences, told phys.org.

"What we're doing is refining plate tectonics-the theory that describes how our planet works-and showing those plates really aren't as pristine as we previously thought," added Russell Pysklywec, a professor in the department of Earth sciences.

The Pacific plate, the largest tectonic plate, constitutes most of the Pacific Ocean floor, stretching along the west coast of North America up to Alaska. At the western edge, it runs from Japan to New Zealand and Australia.

This plate forms a large portion of the Pacific Ring of Fire.

The latest research has identified new points at which the Pacific plate is being pulled down into the mantle.

"It was thought that because the sub-oceanic plateaus are thicker, they should be stronger. But our models and seismic data show it's actually the opposite: the plateaus are weaker," said Gun.

The research team studied four plateaus in the western Pacific Ocean - the Ontong Java, Shatsky, Hess and Manihiki - in a vast area roughly bounded by Hawaii, Japan, New Zealand and Australia. The data was then fed to a supercomputer, which compared it with information collected in studies done in the 1970s and 80s.

"A new finding like this overturns what we've understood and taught about the active Earth. And it shows that there are still radical mysteries about even the grand operation of our evolving planet," said Pysklywec.