TALK TO L ROY BONNER ABOUT HIS RESEARCH, and you’ll hear phrases such as “plunging layer of marine sediment” and “rising magma.” The world beneath his feet still vibrates with the ancient collisions that formed the West.
Through the science of geomagnetics, the Oregon State University senior from Beaverton is peering into the structure of the Earth’s crust with an eye on how the continent is put together and what that might mean for our future.
As a student in physics and the University Honors College, Bonner worked with a team led by Adam Schultz, professor in the College of Earth, Ocean, and Atmospheric Sciences. Schultz also directs the National Geomagnetic Facility at Oregon State.
Bonner spent a month measuring electric and magnetic fields in an area between Mount Rainier and Mount St. Helens in Washington. His project is part of a larger analysis of the structure that underlies the region’s volcanic history.
The signals that Bonner detected stem from thunderstorms, as well as from the interaction of the Earth’s magnetic field with the solar wind, a stream of high-energy particles that constantly bombards the planet. “I’ve always been interested in electromagnetism, and the Earth is the largest system that I can study,” says Bonner, who plans to graduate this spring.
Bonner likes to hike (the Opal Creek Wilderness and his dad’s land near Clackamas are among his favorites) and found that he enjoyed doing fieldwork. “It was surprising to me that you could collect data like this and image everything. It’s all about relating surface measurements of electric and magnetic fields and applying the principles of physics and mathematics to understand what’s going on underground.”
In general, electric currents flow more readily in areas that represent buried marine sediments or contain hot fluids such as magma. In one area near Mount Rainier, Bonner found evidence for both, an ancient part of the seafloor and magma that appears to feed Washington’s largest volcano. “It’s hard to tell the difference from geomagnetics alone,” he says, but he was able to confirm that his observations matched the results of earlier seismic and geomagnetic studies.
“Scientists think a rift opened up (in the distant past), and all this marine sediment piled into it,” says Bonner. “If you can actually identify these materials, you can figure out what happened. It’s helpful for understanding geological processes.”
Bonner plans to continue working with Schultz’s team as a graduate student. He expects to study how electromagnetism in the Earth can affect the nation’s power grid.
