Morristown, TN-- Late Tuesday afternoon dozens of concerned neighbors called Hamblen County 911 to report the earth shaking and the sound of a large blast.
At first the the US Geological Survey reported there was no earthquake in the area.
That prompted local emergency management officials to spend Wednesday looking at other options.
10News spoke with TDEC (Tennessee Department of Environmental Conservation) who ruled out fracking or quarry activity.
Then, we checked with the University of Memphis Center for Earthquake Research and Information, sponsored by the USGS.
Geologist Gary Patterson went and pulled the records from sensors on Tuesday and says he could see activity consistent with an earthquake or quarry blasting.
Emergency Managment Agency Director Chris Bell says there was no licensed blasting in the Hamblen County area on Tuesday.
10News also confirmed with the area's only quarry, Vulcan Materials, that no blasting happened yesterday.
Patterson says the activity shows up over a large area with sensors reporting vibrations in Copper Ridge, Avondale Springs, Green Top, and Lonesome, VA.
He says the USGS doesn't have a lot of sensors in that area which may have resulted in the automated system's failure to report the activity.
Patterson says they need more time to investigate, but either an earthquake or quarry blasting could solve the 'Morristown Mystery.'