Using 20 years of seismic data processed by one of the world’s most powerful supercomputers, scientists have created the first full 3D visualization of a mountain-sized rock called Kumano Pluto buried miles beneath the surface. southern coast of Japan. They can now see that the rock could act as a lightning rod for megaquakes in the region, diverting tectonic energy to points along its sides where several of the region’s largest earthquakes have occurred.
Scientists have known about the pluton for years, but only knew about small portions of it. Thanks to new research by an international team of scientists led by the University of Texas at Austin, researchers now have a comprehensive view of subterranean formation and its effects on the tectonics of the region.
The results will provide essential information for a major new project funded by the Japanese government to determine if another major earthquake is brewing in the Nankai subduction zone, where the pluton is located, said Shuichi Kodaira, director of the Japan Agency for Marine and Earth Sciences. and Technology and co-author of the study published on February 3 in the journal nature geoscience.
“We can’t predict exactly when, where, or how big future earthquakes will be, but by combining our model with monitoring data, we can start estimating processes in the near future,” Kodaira said. who was among the scientists who first spotted signs of Kumano Pluto in 2006. “This will provide very important data for the Japanese public to prepare for the next big earthquake.”
The full extent of the Kumano Pluton has been revealed using UT’s Texas Advanced Computing Center’s LoneStar5 supercomputer to collate 20 years of seismic data into a single high-definition 3D model.
“The fact that we can make such an important discovery in an already well-studied area is, I think, indicative of what may await us in less well-monitored places,” said Adrien Arnulf, assistant research professor at the University. . of the Texas Institute for Geophysics and lead author of the study.
The model shows the region around the Nankai subduction zone, with the earth’s crust bending under the weight of the pluton. In another unexpected find, the pluton was seen diverting buried groundwater into the Earth’s interior. The researchers believe that the pluton’s interference with the larger subduction zone influences the tectonic forces that cause the earthquakes.
Seismic imaging uses sound waves to create images of the earth’s subsoil. Over the years, Japan’s extensive sensor network has collected millions of seismic records from thousands of locations along the Nankai Subduction Zone. The sensors are primarily used to record earthquakes and tremors, but the team has expanded their research to include random recordings of passing scientific surveys using a technique that Arnulf and co-author Dan Bassett, researcher at GNS Science, had honed while working on small-scale projects. in New Zealand. The researchers compiled the huge amounts of information into a single dataset and turned it into a 3D model with the help of LoneStar5.
As well as shedding light on how the Pluto can influence how and where earthquakes occur, the study is a major demonstration of how big data could revolutionize earthquake science. Arnulf plans to use the same methods to create region-scale images in other regions, such as northeast Japan, New Zealand, and Cascadia in the American Pacific Northwest, all of which have subduction zones known to host Earth’s largest earthquakes.
The research was funded by the US National Science Foundation. Additional co-authors include scientists from the Scripps Institution of Oceanography at the University of California, San Diego. UTIG is a research unit of the UT Jackson School of Geosciences.