Effect of error in theoretical Earth tide on calibration of borehole strainmeters
Article first published online: 3 NOV 2010
Copyright 2010 by the American Geophysical Union.
Geophysical Research Letters
Volume 37, Issue 21, November 2010
How to Cite
2010), Effect of error in theoretical Earth tide on calibration of borehole strainmeters, Geophys. Res. Lett., 37, L21303, doi:10.1029/2010GL044454.(
- Issue published online: 3 NOV 2010
- Article first published online: 3 NOV 2010
- Manuscript Accepted: 20 SEP 2010
- Manuscript Revised: 15 SEP 2010
- Manuscript Received: 29 JUN 2010
- Earth tide
 Since the installation of borehole strainmeters into the ground locally distorts the strain in the rock, these strainmeters require calibration from a known source which typically is the Earth tide. Consequently, the accuracy of the observed strain changes from borehole strainmeters depends upon the calibration derived from modeling the Earth tide. Previous work from the mid-1970s, which is replicated here, demonstrate that the theoretical tide can differ by 30% from the tide observed at surface-mounted, long-baseline strainmeters. In spite of possible inaccurate tidal models, many of the 74 borehole strainmeters installed since 2005 can be “calibrated”. However, inaccurate tidal models affect the amplitude and phase of observed transient strain changes which needs to be considered along with the precision of the data from the inherent drift of these borehole instruments. In particular, the error from inaccurate tidal model dominates the error budget in the observation of impulsive, sub-daily, strain-transients.