An “ice quake” on Lake Mendota shook things up along the lakeshore area of the UW-Madison campus Thursday afternoon.

UW-Madison seismology professor Cliff Thurber said the moving ice formed a fault on the surface of the lake, creating a brief tremor-like sensation felt by many people on parts of campus bordering Lake Mendota. The ice quake left a visible ridge in the ice near the shoreline.

“The ice basically wants to expand and it’s stuck within the rim on the lake and has no where to go,” Thurber said. “It ends up thrusting up over itself.” Ice quakes occur because of rapid changes in temperature, much like the recent drop to subzero temperatures in Madison, according to Thurber.

The University of Wisconsin Police Department received several calls around 1 p.m. from people reporting that the buildings they were in shook for a short period of time, according to UWPD officer Jeffrey Ellis.

He said many of the calls came from the Red Gym, Ingraham Hall and Goodnight Hall, all located near the shore of Lake Mendota close to the site of the ice quake.

Ellis said most callers were baffled by the incident. Police contacted UW-Madison’s Physical Plant and determined the shifting ice caused the shaking.

“I’ve been in an earthquake before and I thought maybe it could have been [an earthquake],” said Jill Sakai of University Communications, who felt the ice quake while she was working. “But it’s Wisconsin [and] earthquakes in Wisconsin you don’t really think about.”

Small ice quakes are common in lakes and usually go unnoticed, according to Thurber. He said larger ones that shake the surrounding area happen about every five to 10 years.

For unknown reasons, noticeable ice quakes have been recorded on Lake Mendota, but none have ever occurred on Lake Monona, Thurber said.