Temporal Gravity Observations in Volcanic Areas : Contribution and Limitation of Field Relative Gravimetry
Abstract
Relative gravimetry has been successfully used in the last decades to evidence temporal gravity changes related with ground deformation or mass flux in volcanic areas. Recent instrumental developments in relative gravity data acquisition combined with performances of GPS surveying have significantly improved the sensitivity and the efficiency of the measurement of the gravity field on land. Classical analogical land gravity meters are now advantageously replaced by new generations of microprocessor based instruments allowing automatic measurements digitally recorded along with other useful information. Such improvements offer new potentialities for the study of internal processes through precise surveying or differential continuous recordings. In the meantime, due to intrinsic properties of relative instruments, rigorous and constraining protocols for data acquisition and processing are required to minimize the effects of instrumental drift and possible calibration changes that should be carefully controlled. The combination of relative and absolute gravity measurements then appears as a promising way to study the mass flux associated with the volcanic activity especially in strong topography or island areas. Current potentialities and limitations of relative instruments are discussed here from results of laboratory experiments and field surveys in volcanic areas performed by IRD and IPGP.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2001
- Bibcode:
- 2001AGUFM.G21A..04S
- Keywords:
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- 1200 GEODESY AND GRAVITY;
- 1204 Control surveys;
- 1294 Instruments and techniques