Design and experimental performance data are given of portable tuned seismic transducers for the transmission and reception of seismic signals on the weathered layer of the earth. These transducers are the elastic anlaogue of quarter-wave radio antennas. They are designed for operation with conventional loudspeaker or microphone amplifier. Experimental models of these transducers for nominal 10-watt drive power at 80 plus or minus 1.5 cps are the basic components in active seismic systems for communication, surveillance, and seismic exploration described here in detail. Seismic transmitters and receivers employing electrical and seismic feedback circuits are shown. Construction and operation of phased transducer-transmitter array circuits for the launching of directional seismic waves are described. Seismic signaling and measurement methods employing CW and amplitude, frequency, and phase modulation are described. The results of various experiments with these systems on lake ice and on soil in partially wooded terrain are given in the form of experimental data on communication ranges, power levels, signal-proparation velocities, and signal attenuation in ice and in the weathered layer of the earth; relevant environmental factors are discussed and their influence on the propagation characteristics of seismic signals are shown. Sample recordings of the effects of natural and manmade changes of the seismic- propagation medium and/or of its boundary conditions are demonstrated. The experiences gained and the observations which were made in experiments with various active seismic systems are evaluated with regard to their application for seismic communication, surveillance, and geological exploration. /Author/

  • Corporate Authors:

    Department of the Army

    Electronics Research and Development Laboratories
    Fort Monmouth, NJ  United States 
  • Authors:
    • Ikrath, K
  • Publication Date: 1964-4

Media Info

  • Features: Figures; Tables;
  • Pagination: 98 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00264927
  • Record Type: Publication
  • Report/Paper Numbers: No. 2446 Tech. Rpt.
  • Files: TRIS
  • Created Date: Feb 11 1975 12:00AM