Accession Number : AD0474262

Title :   A TRANSIENT TECHNIQUE FOR SEISMOGRAPH CALIBRATION-MANUAL AND STANDARD SET OF THEORETICAL TRANSIENT RESPONSES.

Descriptive Note : Special rept.,

Corporate Author : LAMONT GEOLOGICAL OBSERVATORY PALISADES NY

Personal Author(s) : Espinosa, A. F. ; Sutton, G. H. ; Miller, H. J.

Report Date : OCT 1965

Pagination or Media Count : 109

Abstract : A transient technique for seismograph calibration was developed and tested by a variety of methods. In the application of this technique a known transient in the form of an electrical signal is injected, through (1) a Willmore-type calibration bridge, or (2) an independent coil, into the seismometer, and the corresponding output transient of the system is recorded. The ratio of the Fourier transform of this transient to that of the input pulse yields phase and relative amplitude response to the seismograph as a function of period. Absolute amplitude response may be calculated if two easily determined constants of the seismometer are known. This technique make practical the daily calibration of continuously recording seismographs without disturbing the instruments more than a very few minutes. The transient technique was tested and proved satisfactory relative to results of more conventional steady-state methods by using both digital and analog analyses of the output transients. Output transiets and the corresponding theoretical response curves have been calculated for 94 sets of instrument parameters. By comparison of the calculated output transients with experimental results it is possible to obtain the response of the instrument with considerable precision, quickly, and without computation. (Author)

Descriptors :   (*SEISMOGRAPHS, CALIBRATION), SEISMIC WAVES, TEST METHODS, PERFORMANCE(ENGINEERING), INTEGRAL TRANSFORMS, ERRORS, TABLES(DATA), COMPUTER PROGRAMMING, INSTRUCTION MANUALS.

Subject Categories : Seismology
      Test Facilities, Equipment and Methods
      Recording and Playback Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE