An Earth Sciences research group at the University of Oregon has landed an article in “Science” magazine. It suggests a new way of judging whether faults like the Cascadia Subduction Zone are able to produce massive earthquakes.
Lead author Quentin Bletery is a postdoctoral fellow. He says before now, people thought the age of the tectonic plates and the speed of their movement contributed to the size of an earthquake, but those theories were thrown off by the two most recent mega-events. Bletery had an idea to look at the geometry of the fault instead:
Bletery: “We took all the subduction faults of the world and we looked at the curvature, which is the changes in the slope of a fault. And what we found is that really big earthquakes happen where this change in the slope is minimal.”
The Cascadia Subduction Zone, which lies off the west coast from Vancouver Island to Northern California is very flat.
Bletery: “That's not a surprise, because we know that like 300 years ago, a huge earthquake occurred in Cascadia.”
While the findings won't help scientists predict the timing of the next big earthquake, it may change where they look. The geometry suggests some known hotspots like the Philippines may be less likely to have huge temblors; other places like Mexico and Peru have a telltale low slope. The article appears in the latest issue of “Science.”