The Army Topographic Command Gravity Program in the western United States

Abstract

The Gravity Division of the Department of Geodesy of the Army Topographic Command (TOPOCOM) (formerly Army Map Service) in Washington, D.C., has been involved in various types of gravity survey operations in the western United States since 1965. The Division, with a staff of approximately twenty‐five, undertakes the following activities: (1) land gravity surveys; (2) coastal and lake bottom gravity surveys; (3) a limited amount of research and development, including new techniques for gravity measurement such as a helicopter gravity measuring system, earth‐tide studies, and improvements in surveying procedures and technology; (4) calibration and maintenance of a large number of LaCoste‐Romberg gravimeters at a laboratory near Herndon, Virginia; (5) development and implementation of procedures and programs for computer reduction of various types of gravity data for geodetic purposes; and (6) financial and administrative monitoring of contracts for procurement of gravity data involving TOPOCOM and various university and government agencies throughout the world.The Department of Defense requires gravity data for various geodetic and mapping purposes. Required gravity coverage for selected land and shallow‐water areas is obtained through (1) field surveys by TOPOCOM personnel, (2) contracts with university, state, or federal groups either engaged in or interested in gravity surveying operations in the selected areas, or (3) cooperative programs involving personnel from TOPOCOM and other agencies or universities. In western North America, TOPOCOM has engaged in gravity survey operations on a contract or cooperative basis with the following groups: (1) the Universities of Washington, Puget Sound, Montana, Oregon, Utah, Arizona, Stanford, California at Santa Barbara, California at San Diego, Hawaii, and MIT; (2) U.S. Geological Survey; (3) California Division of Mines and Geology; (4) the Dominion Observatory in Ottawa, Ontario, Canada.