"Boy, did we have one this morning," Carroll Township resident Michael McCaffrey said.
He was taking a shower and heard a thunderous boom. He thought that his wife, Kathleen, who recently had surgery, might have fallen out of bed. He ran to check on her, and she was fine.
The couple figured it was another earthquake.
"It makes you wonder when they're going to stop - probably never at this point," he said.
The seismic activity in the Dillsburg area - several earthquakes and nearly 460 tremors since Oct. 3 - had seemed to be dwindling in recent months.
The last measurable earthquake shook the area New Year's Eve.
Residents reported booms during the weekend, preceding Wednesday's earthquake, said Jeri Jones of Jones Geological Services.
Jones said he has noticed that the rumblings, which were occurring during the night, are now happening more during the day.
He'll be meeting with township supervisors next month to discuss placing portable seismographs in the area.
Scientists with the Lamont-Doherty Earth Observatory of Columbia University placed portable seismographs in the area last fall to record the tremors and analyze the data.
Senior research scientist Won-Young Kim said in an e-mail Monday that their work is still going on, and he hopes to finalize it in the next couple of weeks.
An earthquake that shook the Dillsburg area Wednesday morning is the 19th one that has been measurable since the fall, said Jeri Jones of Jones Geological Services.
The earthquake at 9:21 a.m. Wednesday measured 1.1 on the Richter Scale.
Three earthquakes measuring 2.0 or greater on the Richter scale have hit the Dillsburg area since the fall. Nearly 460 tremors have been reported in the area since Oct. 3.