Accession Number : AD0480349
Title : MULTICOMPONENT STRAIN SEISMOGRAPH.
Descriptive Note : Quarterly rept. no. 2, 1 Oct-31 Dec 65,
Corporate Author : GEOTECH GARLAND TX
Personal Author(s) : Shopland, Robert C.
Report Date : 15 JAN 1966
Pagination or Media Count : 39
Abstract : Three-component strain and inertial seismographs with matched phase and amplitude responses were developed and field tested at the Wichita Mountains Seismological Observatory. Poor cancellation of seismic noise obtained by summing vertical strain and inertial instruments suggests that the noise might be contaminated with higher mode Rayleigh waves and/or body waves. On the other hand similarity in character of the seismic noise between horizontal strain and horizontal inertial seismographs, together with marked directionality of some of the noise, led to a significant enhancement of signals using a directional strain array. This result may prove to be a breakthrough in the strain program. A special report of preliminary results on enhancement of P waves has been prepared and is appended to this report. A comparison of empirical strain measurements and strain computed from half-space theory indicates a 50% loss of vertical strain for fundamental Rayleigh waves at WMSO. To verify this result, a new variable-capacitance transducer-calibrator was designed to obtain a more reliable calibrator motor constant for the vertical strain seismometer.
Descriptors : (*SEISMOMETERS, SCIENTIFIC RESEARCH), (*SEISMOGRAPHS, SCIENTIFIC RESEARCH), SEISMOLOGY, INSTRUMENTATION, TRANSDUCERS, AMPLIFIERS, MONITORS, STRAIN(MECHANICS), DATA PROCESSING, CALIBRATION, PERFORMANCE(ENGINEERING), NOISE.
Subject Categories : Seismology
Distribution Statement : APPROVED FOR PUBLIC RELEASE