The report includes "relative and absolute gravity data at 321 stations in the San Pedro River Basin of southeastern Arizona since 2000. Data are of three types: observed gravity values and associated free-air, simple Bouguer, and complete Bouguer anomaly values, useful for subsurface-density modeling; high-precision relative-gravity surveys repeated over time, useful for aquifer-storage-change monitoring; and absolute-gravity values, useful as base stations for relative-gravity surveys and for monitoring gravity change over time. The data are compiled, without interpretation, in three spreadsheet files."
[Right, location of gravity stations in Upper San Pedro River Basin. From the USGS report]
Ref: Kennedy, J.R., Winester, D., 2011, Gravity data from the San Pedro River Basin, Cochise County, Arizona: U.S. Geological Survey Open-File Report 2011–1287, 11 p. and data files, available at http://pubs.usgs.gov/of/2011/1287/.