Surface Gravity Effects of Subterranean Tunnels

Abstract

This report determines the change of six components of the symmetric second order tensor associated with the earth's gravity field as a result of the following mass changes and conditions: (1) A tunnel 16 km long is excavated 6m below the earth's surface; (2) A vehicle traveling at a constant speed crosses the tunnel at the earth's surface; (3) The resulting tensor component changes are computed and plotted; (4) The computations are repeated for tunnel depths of 30 and 90 m; and (5) The problem may be inverted from one of subsurface mass removal to one of mass addition above the earth's surface. The results of the report determine that (1) gradiometric detection of large tunnels to a depth of 30 m is feasible, (2) reliable detection of large tunnels deeper than 30 m imposes moderately sophisticated data processing requirements, and (3) detection of tunnels deeper than 90 m is difficult.

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Document Details

Document Type
Technical Report
Publication Date
Jul 16, 1976
Accession Number
ADA030949

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  • TASC, Inc

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  • Energy and Power Technologies

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  • Communication Networks
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