Maryland M 3.6 Earthquake

The image below is a seismogram of the Magnitude 3.6 earthquake Friday, July 16, 2010 at 5:04:47 local time. The first P-waves arrived at Middletown at 05:05:08 am. The location as determined by the USGS is in the Piedmont of Montgomery County, Maryland. It was felt by some people is southern Pennsylvania. More information on this earthquake is at the USGS site at