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Shallow borehole tilt: A reprise

Wyatt Frank K., Morrissey Sean-Thomas, Agnew Duncan Carr. 1988. Journal of Geophysical Research.
Shallow borehole tilt: A reprise
ARTICLE, (1988 ) - PUBLISHEDVERSION - English (en-GB)
Journal of Geophysical Research
OPENACCESS - American Geophysical Union.
Audience : RESEARCHERS
Journal of Geophysical Research
Subject
Geology, info:eu-repo/classification/ddc/551
Domains
Géologie
Description

We describe rsults from nearly a decade of tilt measurements produced by two arrays of shallow borehole tiltmeters: one in a semiarid environment at Pition Flat Observatory (PFO), California (depth of burial 4.5 m) and the other in a maritime-Arctic environment at Adak, Alaska (depth of burial 2 m). Although renovation and reinstallation ofthe instruments atthe two sites reduced thermal noise, it did not change the secular records significantly. This implies thathe large tilts observed reflect instability of the ground rather than the sensor, so that deeper installations should give better results. The PFO data show large rainfall-related tilts(caused by near-surface weathering) and also periodic temperature-related tilts (from several thermoelastic effects). The Adak data are dominated bytilts from the annual temperature cycle (though by a smaller amount than at PFO), but at other frequencies they show essentially the same power levels as at PFO. Both data sets confirm earlier results that burial at such shallow depths, even in apparently stable material, is inadequate for the measurement of tectonic tilts.

Keywords
Language
English (en-GB)
Creators
Wyatt Frank K., Morrissey Sean-Thomas, Agnew Duncan Carr
Contributors
Institute of Geophysics and Planetary Physics - University of California, Department of Earth and Atmospheric Sciences - Saint Louis University
Sources
Journal of Geophysical Research, 93( B8), pp. 9197– 9201, doi:10.1029/JB093iB08p09197
Coverage
Adak, California
Name of newspaper
Journal of Geophysical Research