Open Access2000 hr Comparison of 10 m Quartz‐tube and Quartz‐catenary Tidal Strainmeters
Author(s) -
Sydenham P. H.
Publication year - 1974
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1974.tb04129.x
Subject(s) - quartz , geology , geodesy , catenary , seismology , tube (container) , interferometry , optics , materials science , structural engineering , engineering , physics , composite material , paleontology
Summary Two quartz‐standard tidal‐sensitivity Strainmeters have been installed together. One uses a tube in a somewhat conventional manner, the other a tensioned freely‐hanging catenary of quartz‐links. Constructional details and electronic circuits are presented. Records obtained from each, over a common 3‐month period, enable their performances to be evaluated and positive conclusions about long‐term strain changes to be stated. The instruments have stabilized to provide records that are identical (for periods ranging from 10 s to 500 hr) to within 5 parts in 10 10 sd with a relative drift between them of 5 parts in 10 12 per hour. Coupled with data regarding temperature effects, the results show that mechanical instruments are not necessarily inferior to laser interferometer alternatives and that using the data from a lone instrument of any kind could lead to incorrect conclusions. The close agreement of the two sets of data provides a basis for worthwhile discussion of long‐term rock‐strain secular variations.