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

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

Mike Maurer, the county’s emergency management director, says 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.”

The Free Press of Mankato reports 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.