The gravity station data (5,363 records) were compiled by the U. S. Geological Survey. This data base was received on February 23, 1993. Principal gravity parameters include observed gravity and Free-air anomalies. The observed gravity values are believed referenced to the International Gravity Standardization Net 1971 (IGSN 71). It is also believed the gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula.

The gravity station data (18,461 records) were compiled by the U. S. Geological Survey. This data base was received on February 23, 1993. Principal gravity parameters include observed gravity, Complete Bouguer Gravity anomalies and Free-air anomalies. The observed gravity values are believed referenced to the International Gravity Standardization Net 1971 (IGSN 71). It is also believed the gravity anomaly computation uses the Geodetic Reference System 1967 (GRS 67) theoretical gravity formula.

The gravity station data (6,591 records) were compiled by the U. S. Geological Survey. This data base was received on February 23, 1993. Principal gravity parameters include observed gravity, Free-air anomalies and Bouguer anomalies. 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 gravity station data (41,960 records) were compiled by the U. S. Geological Survey. This data base was received on February 23, 1993. Principal gravity parameters include observed gravity, Free-air anomalies and Bouguer anomalies. 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 gravity station data (1294 records) were compiled by the Alaska Geological Survey and the U.S. Geological Survey, Menlo Park, California. This data base was received in September 1986. Principal gravity parameters include Free-air Anomalies and Simple Bouguer Anomalies (no terrain correction applied) and topographic elevations to compute the anomalies. 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 gravity station data (1294 records) were compiled by the Alaska Geological Survey and the U.S. Geological Survey, Menlo Park, California. This data base was received in September 1986. Principal gravity parameters include Free-air Anomalies and Simple Bouguer Anomalies (no terrain correction applied) and altimeter elevations to compute the anomalies. 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 gravity data (10,629 records) were compiled by Purdue University. This data base was received in December 1989. 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 of central Indiana.

The gravity data (300 records) were compiled by Purdue University. This data base was received in February 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 gravity station data (4,381 records) were compiled by the Japanese Oceanographic Data Center. This data base was received in July 1988. The data are in the 'MGD77' exchange format. Principal gravity parameters include Free-air Anomalies and Observed gravity corrected for Eotvos, drift, and tares. 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 gravity station data (5,905 records) were compiled by the U. S. Geological Survey. This data base was received on July 11, 1997. Principal gravity parameters include observed gravity, Free-air anomalies and Bouguer anomalies. The Bouguer gravity anomaly values were computed using the 1967 gravity formula (International Association of Geodesy, 1971). See Open-File Report 90-265 for further information.