More than a year after Dillsburg residents first noticed earthquake tremors, researchers will host another informational meeting to explain new findings and theories.

The Northern York Emergency Task Force will hold an informational meeting at 7 p.m. Wednesday at the Northern York County High School auditorium, 653 S. Baltimore St. in Dillsburg.

The task force held a meeting last fall when the earthquakes started.

"We'll have more results, a better idea what's happening and where," said geologist Jeri Jones of Jones Geological Services, who has been studying the tremors.

Jones, along with Charles Scharnberger, professor emeritus of geology from Millersville University, and Helen Delano, senior scientist from the state Department of Conservation and Natural Resources Topographic and Geologic Survey in Middletown, will speak at the meeting and take questions from residents afterwards.

"We look forward to an informational, educational and reassuring meeting -- as much as you can be with earthquakes," said Bill Turner, chairman of the board of supervisors for Carroll Township and coordinator for the Northern York Emergency Task Force.

Concern cited: While the tremors aren't quite the magnitude sometimes felt by those in California, Turner said there is reasonable concern among residents, for whom the unexpected tremors can be alarming. Jones said some people have reported cracks in the walls of buildings that they attribute to earthquake damage.

"It's

Advertisement
certainly a shock," Turner said, who experienced a tremor at
his home for the first time recently. He described it as a "small explosion that rattles your windows. Makes you jump up."

The U.S. Geological Survey reported earthquakes with magnitudes of 1.8, 2.6 and 2.8 last month.

Jones said the movement is most likely caused by rock shattering 1,600 feet below the earth's surface.

According to a study led by Won-Young Kim, a seismology researcher at Columbia University, the movement is most likely a result of diabase and sedimentary rock fracturing because of pressure caused by the overall movement of the North American tectonic plate.

Alternate theory: Jones said the meetings will go into further explanation of why this movement has caused hundreds of distinct tremors since October 2008.

He said one theory is hydro seismology, in which higher rainfall collecting in the water table might be causing the rock movement.

He said the main purpose of the meeting, however, will be for residents to have the opportunity to ask the panel questions after a PowerPoint presentation.

"More and more (residents) are experiencing a direct impact," Turner said, because the earthquakes are occurring in new places.

-- Reach Jessica Anderson at 505-5434 or janderson@yorkdispatch.com.