Key to Utah earthquake risks sought in Earth's mantle flow

Wednesday , August 26, 2015 - 12:04 PM

LOGAN — When it comes to understanding earthquakes in interior states like Utah, there are a lot of gaps. But a Utah State University associate professor’s research is working to close those cracks.

Most of our knowledge about earthquakes centers around plate tectonics. But the Wasatch Front remains seismically restless, even though it’s situated well within the North American Plate. The nearest plate boundary, along the San Andreas Fault in California, lies over 750 miles west of Utah.

Scientists know surprisingly little about what’s shaking up Intermountain states, but USU geophysicist Tony Lowry’s research has led him deep into the Earth’s interior, where he’s exploring mantle flow stress.

“We’ve explored various aspects of how and why rocks break and flow, but this is the first time we’ve recognized the importance of deep mantle flow,” Lowry said in a statement. 

Utah falls along the intraplate belt, stretching up through Yellowstone National Park and north to Canada. Working with other researchers from universities in Italy, Massachusetts and throughout the West, Lowry is developing a model to understand what drives earthquakes in the western United States. 

The model incorporates new GPS data from the National Science Foundation’s Earthscope USArray. It weaves in the data with existing research on variations in the thickness and strength of the Earth’s crust and mantle in the Intermountain region.

At first, the research team tried to predict how deep mantle flow contributed to mountains and high-elevation areas in the West. Instead, they found the model works remarkably well in locating earthquake belts based on the upward push of mantle flow. That’s because the deep flow stretches the strong upper mantle layer where earthquakes occur. 

“Our findings represent the birth of a new idea and lay the groundwork for a better understanding of earthquakes,” Lowry said. “We now know we need to be looking for the impetus — that nudge that sets an earthquake system in motion — from flow at depths of 60 to 100 miles, much deeper than where we’d been looking.”

The research is supported by the National Science Foundation, and the team’s findings are published in the Aug. 27, 2015 issue of Nature

Sign up for e-mail news updates.

×