ST. AUGUSTINE, Fla. -- The ground shook briefly this morning, but nobody seems quite sure why.

First Coast News has received several calls, as has the St. Johns County Sheriff's Office, about two tremors felt this morning around 9:30.

Sheriff's deputies are among those who reported feeling the shaking, and the Associated Press reported the tremors were felt in Flagler County as well.

A geologist at the University of Florida said nothing showed up on any earthquake detecting equipment.

The cause of the shaking is speculation at this point, but the sheriff's office said the sensation was stronger near the ocean.

No damage has been reported.