LOUISVILLE, Ky. (WDRB) -- The Louisville Zoo and Louisville Mega Cavern are closed until further notice after a sinkhole was discovered at the zoo. 

Zoo spokesman Kyle Shepherd said engineers are looking at the sinkhole in an undeveloped section of the zoo in the southeast part of the facility. Louisville Mega Cavern also closed Wednesday after an earthquake in Tennessee.

The 3.4 earthquake was recorded on Tuesday afternoon near Knoxville near Maynardville, Tenn. The United States Geological Survey said the earthquake was felt in Kentucky, but officials said they don't believe it's the cause of the sinkhole.

Officials with the Louisville Mega Cavern, which is located under part of the zoo, said it closed Wednesday out of caution. The sinkhole is over the very edge of the mined-out cavern, and some debris did fall in. However, officials said the affected portion of the cavern is isolated and not used.

Shepherd said no buildings are in the section of the zoo where the sinkhole formed. She reiterated that no animals are housed near the sinkhole, so all animals are safe and accounted for.

During a news conference Wednesday afternoon, Emergency Management Director Jodi Meiman said the sinkhole likely formed overnight, between 11 p.m. and 2 a.m., and is estimated to be about 85 yards long by 50 yards wide. 

Meiman said both the zoo and Mega Caverns will remain closed Thursday while officials assess the damage, but people who live in the area should not be concerned. Investigators are keeping a close eye on the sinkhole and the cracks around it to see if it grows.

"We mark them with spray paint, and we see if they get any longer or any wider," Meiman said. "So they're going to have teams here to inspect those through the night, and we'll come back in the morning and see."

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