BGSU geophysicist studies water’s impact on Earth’s crust

Yuning Fu has role in NASA’s Earth Surface and Interior grant research

Dr. Yuning Fu, a geophysicist with the Bowling Green State University School of Earth, Environment and Society, is intrigued by what causes the Earth’s crust to move up and down, and what impact that has on earthquake activity.

Fu came to BGSU two years ago by way of Alaska and California, where he was involved in research to look at how the Earth’s crust deforms or responds from the change in surface water.

Fu and his University of California, Berkeley scientist-colleagues (Dr. Roland Bürgmann and graduate student Christopher Johnson) determined the movement of the crust is, indeed, impacted by rain water and snow, and that this stress change of the Earth’s crust causes seasonal, small increases in earthquakes.  

Due to the accuracy of Global Positioning Systems, they could measure the change in the Earth’s crust in California’s Sierra Nevada mountains and Coast Ranges throughout the year.  

Their measurements allowed them to determine how much snow accumulated during the winter and how much snow melted during the summer.  

During the winter, they found the Sierra Nevada mountains were pushed down by about a centimeter because of the load of snow and water; during the summer and early fall, when the water had melted and flowed downhill, the Earth’s crust would “flex, pushing and pulling on the state’s faults,” according to their paper published in Science in June.

Identifying “the movement of the crust very accurately was the first part of the work we were doing,” Fu explained. “After that, we wanted to see if the water load change for this part of California that causes stress change on the active fault might trigger earthquakes.”

“We used a numerical-physical model and found these are related,” he continued. “In late summer and early fall we were seeing more small magnitude earthquakes on the San Andreas Fault, because the surface water mass decreases and unclamps the fault.".

The work doesn’t stop there though. He is continuing the research and is part of a NASA Earth Surface and Interior three-year grant to use satellite data to more accurately measure water resources and investigate the relationship with seasonal seismicity change in Alaska, California and other active tectonic plates on the West Coast.  

NASA is funding BGSU's approximately $180,000 for this project. Much of his research will be in Alaska, where he discovered his passion for studying the movement of the Earth’s crust while working on his Ph.D. in geophysics at the University of Alaska, Fairbanks.