PACES Online Gravity Database

This database is part of a collaborative effort by the U.S. Geological Survey, the National Imagery and Mapping Administration (NIMA) National Oceanic and Atmospheric Administration (NOAA), NSF, NASA and The University of Texas at El Paso. The gravity datasets available here are for the U.S. and abroad.

The data available from this web site are based on national data sets that have been complied from a vast number of sources. Virtually all such compilations begin with a data set that has been compiled by the National Image and Mapping Agency. Various groups have then worked to enhance this data set by making additions and refinements. For example, in the 1980's, the Society of Exploration Geophysicists and the Geological Society of America conducted such efforts and constructed continental scale maps. There is good coordination between these groups, but duplication of data points and minor discrepancies due computer systems are inevitable. However, numerical differences probably introduce only very small errors into the database (~0.1 mGal). The most significant but subtle source of error in the final calculated anomaly values is not the gravity reading itself but the elevation determination at the location of the gravity reading. The vast majority of the gravity readings in this (and related data bases) were taken before GPS technology was widely employed. Thus, a wide variety of techniques have been used to measure or estimate the elevations in this database. Since the calculated Bouguer anomaly value varies by about 0.06 mGal/ft, an error of 5 ft in elevation (a typical uncertainty in many cases) will introduction an error of about 0.3 mGal in the Bouguer anomaly value. Although small for many applications, this level of error should be kept in mind when using these data. Uncertainties due to the use of a single density value for the Bouguer and terrain corrections are the same as for any other database. For these not familiar with the reduction of gravity data, a tutorial "Getting Started" and an overview of gravity reduction procedures are provided.

Enter database

---

© 1995-2003 PACES. All Rights Reserved

This site designed for
Microsoft Internet Explorer 5+ and small fonts.

Please direct questions and comments to:
PACESwebmaster@geo.utep.edu

Web development and implementation by:
Mr. Roberto Torres
Computer Science Department
University of Texas at El Paso,
El Paso, Texas, USA