The gravity station data (152,624 records) were compiled by the University of Texas at Dallas. This data base was received in June 1992. Principal gravity parameters include Free-air Anomalies and Simple Bouguer Anomalies (no terrain correction applied). The observed gravity values are referenced to the International Gravity Standardization Net 1971 (IGSN 71). The gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula. The data are randomly distributed within the boundaries and offshore of South America.

The gravity station data (59,933 records) were compiled by various organizations. This data base was received in June, 1993. Principal gravity parameters include Free-air Anomalies and Simple Bouguer Anomalies (no terrain correction applied). The following assumptions have been made: the observed gravity values are referenced to the International Gravity Standardization Net 1971 (IGSN 71); the gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula.

The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity parameters include Free-air Anomalies and Bouguer Anomalies (terrain and mass corrected). The gravity station data have been adjusted to the International Gravity Standardization Net 1971 (IGSN 71). The gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula. The data are randomly distributed within the area bounded by 64 - 71 degrees West and 20 - 29 degrees South in the Central Andes of South America.

The gravity station data (1,522 records) were compiled by the Portland State University. This data base was received in August 1990. Principal gravity parameters include Free-air Anomalies and Complete Bouguer Anomalies (terrain correction applied). The observed gravity values are referenced to the International Gravity Standardization Net 1971 (IGSN 71). The gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula. The data are randomly distributed within the boundaries of the greater Portland area.

The Decade of North American Geology (DNAG) gravity grid values, spaced at 6 km, were used to produce the Gravity Anomaly Map of North America (1987; scale 1:5,000,000). Considerable caution should be exercised when using these gridded data in regions of sparse coverage (for example, deep oceanic areas). The spatial distribution of the original data from which the grid was generated is shown on sheet 5 of the published map. Note: There are no gridded data values for Mexico.

The gravity station data (55,907 records) were gathered by various governmental organizations (and academia) using a variety of methods. This data base was received in March 1993. Principal gravity parameters include Free-air Anomalies and Simple Bouguer Anomalies (no terrain correction applied). The observed gravity values are referenced to the International Gravity Standardization Net 1971 (IGSN 71) and the gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula. The spatial resolution of the data is randomly distributed within the boundaries of Minnesota.

The gravity station data (1,633,499 records) were gathered by various governmental organizations (and academia) using a variety of methods. This data base was received in March 1999. Principal gravity parameters include Free-air Anomalies and Simple Bouguer Anomalies (with terrain correction applied only in areas where substantial variations in local topography exist). The gravity station data has been adjusted to the International Gravity Standardization Net 1971 (IGSN 71) and the gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula. The data are randomly distributed within the boundaries of the U.S., Alaska and Hawaii.

The gravity station data (3814 records) were compiled by Professor Ervin. This data base was received in April 1993. Principal gravity parameters include Free-Air Anomalies and Simple Bouguer Anomalies (no terrain correction applied). The observed gravity values are referenced to the International Gravity Standardization Net 1971 (IGSN 71). The gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula. The data are randomly distributed within the area of northwestern Wisconsin north of 45 degrees north latitude.

The gravity station data (898 records) were compiled by Professor Ervin. This data base was received in January 1987. Principal gravity parameters include Free-Air Anomalies and Simple Bouguer Anomalies (no terrain correction applied). The observed gravity values are referenced to the International Gravity Standardization Net 1971 (IGSN 71). The gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula. The data are randomly distributed within the prentice area of northern Wisconsin.

Gravity data for the entire state of Nevada and adjacent parts of California, Utah, and Arizona are presented. About 80,000 gravity stations were compiled primarily by the U.S. Geological Survey. Gravity data were reduced to the Geodetic Reference System of 1967 and adjusted to the International Gravity Standardization Net 1971 gravity datum. Data were processed to complete Bouguer and isostatic gravity anomalies by applying standard gravity corrections including terrain corrections and isostatic corrections. This data set was received in October, 1997 as a published USGS CD-ROM. For further information, see "Gravity Data of Nevada, by David A. Ponce, U.S. Geological Survey Digital Data Series DDS-42, 1997". A documentation file(readme.txt), describes the contents of this collection and includes a description of the data reduction process, selected principal fact references, and a list of sources for the data.