Terrestrial Gravimetry and the Development of Absolute Gravimeters
Abstract
By extending the reach of our hands and quickening the response of our eyes, measurement methods and instrumental capabilities have driven and made possible much of scientific progress. By the middle of the nineteenth century, measurement capabilities for g had reached a precision of 1 in 106 and an accuracy of 1 in 105. Over the past 40 years, instruments have evolved to the point where measurements can be made at the parts in 109 level of precision and, in the case of absolute instruments, accuracy. In this talk, reasons will be given for this remarkable progress (4 orders of magnitude improvement in 40 years) in our ability to measure g. In the context of this session's title, ``New Sensors of Our Planet,'' our recent---probably for one of us (JF) the last---development of a truly portable absolute gravimeter will be described. This small and portable absolute instrument drops a test mass 200 times a second while keeping the center of mass of the apparatus fixed---to avoid recoil effects---during the entire measurement cycle. The capabilities of this μ gal-accuracy instrument will be demonstrated.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2004
- Bibcode:
- 2004AGUSM.G43C..01F
- Keywords:
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- 0920 Gravity methods;
- 0994 Instruments and techniques;
- 1219 Local gravity anomalies and crustal structure;
- 1242 Seismic deformations (7205);
- 1244 Standards and absolute measurements