Engineering topics

Wyatt, F.

Publications and source records attributed to Wyatt, F..

4 records

NASA NTRS1984

Comparing tiltmeters for crustal deformation measurement - A preliminary report

Attention is given to 1.2 years of data from two Michelson-Gale long fluid tiltmeters, one long center pressure tiltmeter, and a shallow borehole tiltmeter, which have been in operation at Pinon Flat Observatory in Southern California. The most stable tilt record shows a secular rate of 0.28 microrad/a, which may be real. Comparisons undertaken among instruments have identified more and less successful measurement techniques. It is concluded that even the best existing sensors must be improved in order to measure continuous tectonic motions.

Wyatt, F.↗

NASA NTRS1984

High precision measurements in crustal dynamic studies

The development of high-precision instrumentation for monitoring benchmark stability and evaluating coseismic strain and tilt signals is reviewed. Laser strainmeter and tilt observations are presented. Examples of coseismic deformation in several geographic locations are given. Evidence suggests that the Earth undergoes elastic response to abrupt faulting.

Wyatt, F.↗

NASA NTRS1981

The seismotectonics of plate boundaries

Research on the seismotectonics of plate boundaries is summarized. Instrumental development and an observational program designed to study various aspects of the seismotectonics of southern California and the northern Gulf of California are described. A unique superconducting gravimeter was further developed and supported under this program for deployment and operation at several sites. Work on Earth tides is also discussed.

Berger, J.↗

NASA NTRS1980

Investigations of tilt measurements using shallow borehole tiltmeters

An array of shallow borehole tiltmeters has been operated at Pinon Flat Observatory since early in 1977. The data from this array are examined for coherence between the individual instruments and compared with the corresponding data from three 732-m laser strainmeters. In general, there is no significant coherence between the signals from the tiltmeters outside the microseismic and tidal bands even though they are spaced as closely as 10 m apart. Comparisons with the strain records show that the observed tilt noise power exceeds the strain noise power by 25-40 dB over the band from 0.000001 to 1 Hz. Analysis of the coherence estimates establishes the necessity for an unacceptably large (approximately 1000) array of instruments in order to determine the common tectonic signals. The observed secular tilt rates are from 40 to 450 times the observed secular strain rates for the same period. The theoretical noise power limit of the tilt transducer renders the instrument incapable of recording background noise at a quiet site over the band from 0.0001 to 0.1 Hz.

Wyatt, F.↗