The puzzle pieces of tectonic plates that make up the outer layer of earth are not rigid¹ and don't fit together as nicely as we were taught in high school. A study published in the journal Geology by Corné Kreemer, an associate professor at the University of Nevada, Reno, and his colleague Richard Gordon of Rice University, quantifies deformation³ of the Pacific plate and challenges the central approximation of the plate tectonic paradigm⁴ that plates are rigid.

 

Using large-scale numerical modeling as well as GPS velocities⁵ from the largest GPS data-processing center in the world -- the Nevada Geodetic Laboratory at the University of Nevada, Reno -- Kreemer and Gordon have showed that cooling of the lithosphere⁶, the outermost⁷ layer of Earth, makes some sections of the Pacific plate contract horizontally at faster rates than other sections. This causes the plate to deform².

 

Gordon's idea is that the plate cooling, which makes the ocean deeper, also affects horizontal movement and that there is shortening and deformation of the plates due to the cooling. In partnering with Kreemer, the two put their ideas and expertise⁸ together to show that the deformation could explain why some parts of the plate tectonic puzzle didn't fall neatly⁹ into place in recent plate motion models, which is based on spreading rates along mid-oceanic ridges¹⁰. Kreemer and Gordon also showed that there is a positive correlation¹¹ between where the plate is predicted to deform and where intraplate earthquakes occur. Their work was supported by the National Science Foundation.

 

Results of the study suggest that plate-scale horizontal thermal¹² contraction¹³ is significant, and that it may be partly released seismically¹⁴. . The pair of researchers are, as the saying goes, rewriting the textbooks.

 

"This is plate tectonics 2.0, it revolutionizes the concepts of plate rigidity," Kreemer, who teaches in the University's College of Science, said. "We have shown that the Pacific plate deforms¹⁵, that it is pliable¹⁶. We are refining the plate tectonic theory and have come up with an explanation for mid-plate seismicity."

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