Scientists Reassure Pennsylvania Residents in Quake Swarms

Scientists have met with residents of a central Pennsylvania town to reassure them about the hundreds of tiny earthquakes the area has experienced over the past year.

Charles Scharnberger, Millersville University professor emeritus of geology, says fracturing rock is to blame for the approximately 817 tremors recorded since October 2008. He says a lot of earthquake activity is cyclical, and it can take years for stress to build up enough to cause them.

But Scharnberger says residents shouldn’t worry about a stronger and more damaging earthquake, since there are no fault lines in the area. He says the quakes on the east coast occur where different types of rock intersect.

Jeri Jones of Jones Geological Services says higher than average rainfall collecting in the water table might be triggering the movement of rock.