The seismometer located at Brandywine Creek State Park is positioned on the Wissahickon Formation. The Wissahickon Formation is an extensive sequence of pelitic and psammitic gneisses interlayered with amphibolites. With few exceptions, most of the amphibolite layers are less than 30 feet thick. The rocks have been metamorphosed to upper amphibolite facies and isoclinally folded.

The formation is located within the Wilmington North, Kennett Square, West Grove, Newark West, and Newark East quadrangles.

Seismometer: HS101-A Short period Vertical
Amplifier: Emtel 6243 Gain 36dB
VCO: 2720 Hz

Latitude: 39.79944
Longitude: -75.57667
Elevation: 63 meters above sea level