The (Richter) magnitude 2.5 earthquake was the largest of 11 shocks recorded on July 27 and 28 from Culpeper, VA. The M=2.5 event occurred on Sunday, the 27th, at 11:10:43.2 EDT at latitude 38.43°N, longitude 77.98°W, depth 19 km based on the VTSO location using three stations at epicentral distances of 35 to 75 km. This location is about 4 miles south of the Wal-Mart which was evacuated because of objects falling from shelves and the Superfresh grocery store at which cold cuts fell down in the freezer. The instrumental location is not very well constrained because all the locating stations are to the souths.
Other events in the sequence which may heen felt occurred on Sunday the 27th at 7:41 AM (M=1.1), 8:23 AM (M=0.8), 10:22 AM (M=1.1), 10:43 AM (M=1.1), 11:09 AM (M=1.4 -- 40 seconds before the M=2.5 event), and 11:52 AM (M=1.4). All times are in EDT.
Click here for a map showing the VTSO location, and click here for a figure shoiwng the vertical-component seismograms at stations NA12, GHV and CVL showing arrivals from both the M=2.5 event and one which preceded it by about 40 seconds. For individual-channel waveforms, click here and then go to the desired subdirectory (97208XXXX, where XXXX is the hour and minute in GMT, which is four hours later that EDT).
Although there is no record of earthquakes in Culpeper, such "swarms" are not unusual in the Piedmont in the east.
Last updated: 1 August 1997