Optical fiber interferometers for referencing surface benchmarks to depth

Citation:
Zumberge, MA, Wyatt FK.  1998.  Optical fiber interferometers for referencing surface benchmarks to depth. Pure and Applied Geophysics. 152:221-246.

Date Published:

Jul

Keywords:

benchmarks, optical fibers, strainmeters, tiltmeters, tilts

Abstract:

We have developed and operated optical fiber interferometers for monitoring displacements within boreholes, as part of a program of crustal deformation measurement. These optical tiber strainmeters-a total of twelve instruments at two sites in southern California-were installed to sense the motion of the end-monuments of much longer baseline strainmeters and tiltmeters, allowing correction for any near-surface ground movement. One of the installations was specifically designed to investigate the distribution of deformation with depth, measuring over several borehole length-intervals from 5 m to 50 m. The displacements recorded over year-long time scales along these length intervals range up to 6 mm and show internal consistency and stability at the 50 mu m level. The use of these interferometers to provide correction signals for kilometer-scale crustal strain measurements has resulted in greatly improved records.

Notes:

n/a

Website

DOI:

10.1007/s000240050152