Shaking ground in central Minnesota left residents of Mankato asking Tuesday morning if they’d just experienced an earthquake. It in fact turns out that it wasn’t an earthquake.
On Monday at 11:04 a.m. a controlled blast was conducted in the quarry at 900 Cleveland Avenue. Afterwards, a vibration was felt through most of the city. It is suspected that due to weather, overpressure may have caused a “pressure wave,” Mankato city officials said. The U.S. Geological Survey listed the blast as having the same magnitude of an earthquake measuring 2.8 on the Richter scale.
Jordan Sands has suspended all blasts at this site until further notice, according to a news release. City officials say the incident is under investigation. BEC Emergency Management Director Mike Maurer said there have been no reports of significant damage, and Mankato police are now handling the investigation.
Local Kasota stone is prized for its color and variations and is used in construction around the world and has been mined in the area for more than 100 years.
There are two quarries in the Mankato area, but they are mostly unseen by residents and mining has stopped at the Mankato Quarry located near Madison Avenue and Riverfront Drive. The still operating Jefferson Quarry begins just north of Pine Street and parallels the Minnesota River.