LIMA, Ohio - A small earthquake rumbled lightly under one of Ohio's active seismic zones, but didn't cause any damage.
In fact, authorities in Lima said yesterday they were unaware of the 2.8-magnitude earthquake, which lasted a few seconds Thursday night.
The Ohio Seismic Network reported that the quake occurred at 9:51 p.m. Thursday and was centered about eight miles west of Lima, said Mike Hansen, the network's coordinator.
No injuries were reported, the Allen County Sheriff's Office said.
Donald Stierman, associate professor of geophysics at the University of Toledo, said the university's seismograph did not record the quake because the instrument is not sensitive enough for that slight a movement, and because of the "background noise" it picked up that evening.
It was probably a shallow event," he said. "We wouldn't have felt anything this far away."
Lima is about 70 miles southwest of Toledo.
The university is installing a digital seismograph later this summer that will improve on the older drum types, he said.
Mr. Hansen said the quake occurred in the Anna Seismic Zone, an area of northwest and western Ohio named for the town of Anna in Shelby County.
"That's traditionally part of our most active seismic zone in Ohio, but it's been quiet for the last decade or so," he said.
Seven earthquakes have been recorded in northeast Ohio this year, with the strongest producing a magnitude of 3.0, Mr. Hansen said.
The Allen County Emergency Management Agency said it was unaware of the event.