The grids provided here are: <br /> "FAA_1000_UTM18N_NAD83.gxf" : Gravitational Free-air anomaly (mGal) with a 1-km
half-wavelength grid filter <br /> "BA_267_1000_UTM18N_NAD83.gxf": the Bouguer anomaly (mGal) derived from the above
free-air anomaly assuming a reference density of 2.67 g/m3. <br /> <br /> Grids are in the ASCII grid exchange format
(.gxf). Header information provides the grid dimensions, separation, coordinates and map projection, and z-value range information.
The grid values follow. <br /> <br /> The projected coordinate system used for all grids is UTM Zone 18N: <br /> Datum: NAD83
<br /> Base Latitude: 0.00 degrees <br /> Central Meridian: -75.00 degrees <br /> False Easting: 500,000 meters <br
/> False Northing: 0 meters <br /> Scale factor at natural origin: 0.9996 <br /> <br /> Detailed information regarding data
collection and processing can be found in the <a href="https://www.sciencebase.gov/catalog/item/53f5a9c9e4b09d12e0e86438">
technical report</a>. <br /> <br /> These data should be cited as follows: Shah, A., 2014. Airborne Geophysical Surveys over
the 2011 Mineral, Virginia Earthquake Area. U.S. Geological Survey ScienceBase. Data files and documentation. doi: 10.5066/F78K773V.
Access date.