MANKATO — Authorities said a quarry blast — not an earthquake — apparently caused the ground to shake in Mankato.

Tremors were felt throughout the city at about 11 a.m. Tuesday. The Blue Earth County Sheriff’s Office said the shaking apparently came from a blast at Jefferson Quarry.

Mike Maurer, the county’s emergency management director, said there were no reports of major damage.

The city of Mankato said in a news release a vibration felt through most of the city may have been due to weather, with overpressure causing a “pressure wave.”

According to a press release, the dispatch center was overwhelmed with 911 calls.

Some residents said they felt like their homes were going to collapse.

The explosion shook the historic courthouse, temporarily halting a county board meeting.