Two CWU professors part of research team acclaimed for ‘icequake’ study

Central Washington University Geological Sciences faculty members Dr. Audrey Huerta and Dr. Paul Winberry participated in a multi-institutional research project in Antarctica that was published this summer in the Journal of Geophysical Research: Earth Surface.

The study, featured recently on the Pennsylvania State University website, found that a seismic phenomenon called “icequakes”—similar to an earthquake but caused by the movement of ice instead of rock—are likely responsible for causing the ground in Antarctica to tremble.

The research team, led by Penn State doctoral candidate Erica Lucas and her adviser, Penn State Professor of Geosciences Andrew Nyblade, found that icequakes are driven by ocean tides at a major ice stream in West Antarctica.  

Over a five-year period, seismic monitors captured more than 2,200 icequakes at the Foundation Ice Stream in West Antarctica. Ice streams are fast-flowing regions of ice that act like a drainage system carrying ice from the land to the ocean. The research team found that the icequakes largely occurred during spring tides.

“Tides are driven by the orbits of the moon and Earth, and it’s fascinating to be able to make a connection between tides and ice processes on Earth,” Lucas said in the article on psu.edu.

Scientists also found the large majority of the icequakes at the Foundation Ice Stream occurred around the grounding line—the zone where the ice sheet transitions from sitting on bedrock to floating on the ocean.

As explained in the article, these floating ice shelves act as buttresses, preventing land ice from flowing into the ocean, so understanding the processes happening in these regions is especially important, the scientists said.

Using the data collected since 2018, the scientists observed a distinct seasonal shift in the time of day the seismic events occurred, which coincided with the timing of daily high tides throughout the year.

Joining Huerta, Winberry, Lucas, and Nyblade on the research team were Richard Aster of Colorado State University; Douglas Wiens of Washington University in St. Louis; and Terry Wilson of Ohio State University.