Accession Number : AD0427206


Title :   THE REQUIREMENTS OF A HIGH-SENSITIVITY SEISMOGRAPH STATION,


Corporate Author : MICHIGAN UNIV ANN ARBOR INST OF SCIENCE AND TECHNOLOGY


Personal Author(s) : Carder,Dean S


Report Date : Oct 1963


Pagination or Media Count : 72


Abstract : The efficiency of a short-period seismograph is regulated largely by the nature and magnitude of the so-called background noise prevalent at the station. This background noise is more or less continuous and varies from place to place and from time to time. Effects of this noise may be reduced by (1) selecting a station site where the noise is low, either remote from noise sources, in the shadow of noise barriers, or deep underground; or by (2) the use of frequency and wavelength filters. Frequency filters are in large part ineffective because the signals we wish to measure have the same frequency (from 0.5 to 5 cps) as the noise; and wavelength filters require the use of expensive arrays. This report discusses possible sources and methods of propagation of background noise and the selection of optimum sites and methods for reducing the effect of noise. Present and suggested future arrays are included in this discussion. Highly sensitive seismograph stations and instruments in current operation are described, and comparisons are made of the ability of some of the better stations to record magnitude 4 to 5.5 earthquakes. Suggested designs of unmanned and other special-purpose seismic stations are included. (Author)


Descriptors :   *SEISMOLOGICAL STATIONS , SENSITIVITY , BACKGROUND , NOISE , SELECTION , SEISMOGRAPHS


Distribution Statement : APPROVED FOR PUBLIC RELEASE