April 24, 2009 Dillsburg, Pennsylvania Earthquake

Region: Dillsburg, Pennsylvania
Date-Time: 2009-04-24, 05:36:48.8 (UTC)
Date-Time: 2009-04-24 01:36:48.8 (EDT)
Magnitude: 2.9 (Mc - Coda Duration)
Latitude: 40.064 N
Longitude: 77.026 W
Depth: 1.5 km

Epicenter Map

A Community Internet Intensity Map

Felt reports by residents via the Internet

Seismic records from some selected stations (Earthquake on 04/24/2009 05:36:48 UTC)

Earthquakes that occurred in northern York County, PA, during 10/05/2008-04/24/2009


The Dillsburg area, York County, Pennsylvania experienced small earthquakes since early October 2008. 24 small earthquakes were detected and located by LCSN during October 5, 2008 through April 24, 2009. These shocks are very small ranging in magnitude 0.8 and 2.9. The magnitude 2.9 event on April 24, 2009 is the largest among these shocks. During October 5, 2008 and December 31, 2008, hundreds of microearthquakes occurred in the area as an earthquake swarm.

  • List of earthquakes during 10/05/2008 - 04/24/2009 in the region

    Recent Dillsburg, York County, Pennsylvania earthquake sequence has been relatively poorly recorded by regional and national seismographic network stations when compared with other earthquakes that occurred in the northeastern United States. There are only four stations within 100 km from the epicenter and the nearest station, MVL (Millersville University), was about 53 km away from the epicenter (see the map above).

    Hence, the location of the largest shock (mainshock) on 10/10/2008 at 04:22:07 EDT as well as much smaller foreshocks and aftershocks were poorly determined, which can be seen from the widely scattered epicenters of those earthquakes. Usually, foreshocks, mainshock and aftershocks of such small sized earthquake sequence will occur very close to each other as a "cluster".

    24 small earthquakes that occurred around Dillsburg since Oct. 5th, 2008 until Apr. 24, 2009 are plotted with red circles. The circle size is proportional to magnitude of each event.

    The permanent seismographic stations of the LCSN are plotted with solid triangles: MVL (Millerville University), FMPA (Franklin and Marshall College). Other earthquakes that occurred in the region are plotted with open circles. The largest event was magnitude 4.1 that occurred on 04/23/1984 in Lacaster seismic zone.

    Waveform (seed volume for the event, 04/24/2009 05:36:48 UTC)


    Additional links

    Compiled by Won-Young Kim
    at Lamont-Doherty Earth Observatory of Columbia University, Apr. 2009