MADISON, Wis. -- University of Wisconsin-Madison geologists said the shaking some University of Wisconsin-Madison staffers and others felt Thursday afternoon near Lake Mendota was most likely an ice quake caused by ice shifting on Lake Mendota.

UW-Madison geologists said they recorded a tremor at 12:50 p.m. that lasted a few seconds.

Ice quakes are usually accompanied by loud cracking noises, and the university said a number of people called UW police and facilities staff to inquire about the rumbling disturbance.

Brad Bolden was fishing on Lake Mendota during the incident.

"The ice moved 2 feet. It was a good 2 feet. I don't know where it went, because it didn't move up to the shore, but it moved a good 2 feet," Bolden said.

Anna Slate, a UW-Madison sophomore, was studying when she experienced the tremor.

"I had no idea (what it was). I thought it was construction or something. I was in the library studying and there was just a very loud shake," Slate said.

The ice quake also caused a loud crack and left behind a pressure ridge on Lake Mendota.

UW-Madison seismologist Cliff Thurber said ice quakes are caused by large shifts in ice and often triggered by drastic temperature changes -- similar to those seen in the past few days.

"It happens because we had a period of very cold weather, and the ice contracts when it's cold, and in a period of warmer weather like right now, it expands in its pressure. And the pressure buckles the ice and that (causes it to) crack," said Jim Kitchell, UW-Madison director of Limnology.

Kitchell said that in his 37 years working on the shore of Lake Mendota, ice quakes are actually a common occurrence.

"It doesn't always happen during the daylight periods. It happens more at night when the temperature changes are stronger," Kitchell said.

The ice quake was too small to cause any damage, but experts said it was the strongest ice quake the area has seen in nearly a decade. However, experts said the ice on Lake Mendota is still thick enough to safely walk and fish on.