Accession Number:

AD0729916

Title:

Experimental and Theoretical Studies of Long-Period Tilt of Earth's Crust: Part I. Experimental.

Descriptive Note:

Final rept. (Part 1), 9 Dec 69-9 Jul 71,

Corporate Author:

LITTLE (ARTHUR D) INC CAMBRIDGE MASS

Personal Author(s):

• Simon,Ivan

Report Date:

1971-07-09

Pagination or Media Count:

74.0

Abstract:

A three-element borehole tiltmeter system was developed and installed at Bedford, Massachusetts for the purpose of measurement and analysis of crustal tilts. Each borehole unit contains two single-axis tiltmeters with diamagnetically suspended masses and leveling motors adapted for stepwise calibration in situ. Individual wellhead electronic units contain regulated power supplies, low-pass filter-amplifiers and controls for remote leveling. Output signals are transmitted by cables to a central terminal where they are monitored with strip-chart recorders and recorded by a multi-channel digital tape recorder. The three boreholes, 50 to 56 ft. deep and approximately 600 feet apart, are in a compact, foliated granitic gneiss overlain by 3 to 10 ft. of overburden. They have steel casing extending approximately 20 feet below surface. Water level stands approximately 8 - 10 ft. below the surface. The system has been in operation for over a year now and considerable amount of data on tidal tilts and their perturbations was obtained. Author

Descriptors:

• *TIDES
• DEFORMATION
• LITHOSPHERE
• MEASURING INSTRUMENTS
• LOW PASS FILTERS
• OPERATION
• SENSITIVITY

Subject Categories:

• Geology, Geochemistry and Mineralogy
• Test Facilities, Equipment and Methods

Distribution Statement:

APPROVED FOR PUBLIC RELEASE