A series of small earthquakes this month in the Reno area has left some to wonder what's behind the tremors and if more -or stronger - events are possible.
"You hear people talking and they want to know: 'Just what exactly is going on around here?'" said Reno resident Ron Hill, 70. "By now, you've got the feeling something under us isn't quite right."
Until recently, the Marietta area had no history of generating quakes, according to the Ohio Seismic Network. That all changed Oct. 24, 2010, when many living in the Reno area reported hearing a loud "boom" that followed with a brief shake.
Since Aug. 24, four quakes have been felt locally, with the latest on Sept. 4. Epicenters for three of the quakes were determined to have been at different points around the Reno area. The Aug. 24 quake was centered in Virginia.
Michael Hansen, coordinator of the Ohio Seismic Network, said the recent tremors, which ranged from 2.6 to 3.1 on the richter scale, don't mean a bigger earthquake is coming, although that can't be ruled out, either.
It generally takes a quake in the 4.0 to 5.0 range before damage is reported, Hansen said. The largest quake centered in Ohio was a 5.4-magnitude in Shelby County that was recorded in 1937. There was a 5.0 quake east of Cleveland in 1986 that caused minor damage. Otherwise, damaging quakes in the state are rare.
Quakes centered near Reno:
2.8 richter scale; 4:12 a.m., Oct. 24, 2010.
3.0 richter scale; 5:35 a.m., Aug. 31.
3.1 richter scale; 1:36 p.m. Aug. 31.
2.6 richter scale; 9:22 a.m. Sept. 4.
"We just can't predict earthquakes," he said. "I can't say if you'll have more, or no more. These have all been relatively small and not large enough to cause damage. Could we have a bigger one? There's no way to know but I would say it would be very unlikely to have a quake with catastrophic damage."
Hansen said the recent seismic activity in Marietta has prompted talks about establishing a seismic recording station closer to Marietta. The seismic network has 24 recording stations across the state, most at universities. The nearest station is on the Ohio University Campus in Athens.
"We've been able to record data from these quakes from as far north as Youngstown and in central Ohio we picked it up, too," he said. "But having a station nearby would allow us to record the events more clearly and give us a better ability to pick up smaller events that may be occurring without anyone realizing they're happening."
Anyone who feels a quake is asked to call or submit a report to the Ohio Seismic Network. After the recent earthquakes, several people phoned local police, which is not advised unless there is injury, serious damage or an odor of gas.
Reno resident Janice Arnold said she stopped counting the events because "they're almost a way of life now."
"There's been several," she said. "I know I've felt at least three ... They've all been similar -the house shook and you just noticed something wasn't normal."
Arnold said she's not concerned about a larger-scale event, though.
"There's not a lot you can do about it, anyway," she said.
Hansen said the recent quakes are still being studied but that it appears they are all "shallow events," meaning they were three to 10 miles beneath the surface.
"You've had a build-up of stress that popped off several small earthquakes and sometimes after a series of events like this it takes time for stress to build back up," he said. "That's not to say you won't have another one ... But I don't think people need to have a great deal of worry or stress."