A NEW WIDE-BAND (1 MHZ TO 100 HZ) SEISMIC SPECTROMETER

A new instrument has been developed to measure the compressional atten uation and Young's modulus of rocks in the seismic-frequency range. Th is instrument has been calibrated over a frequency range from 1 mHz to 100 Hz at a strain of about 2.5 X 10(-6). The attenuation of the samp le is calculated from a relative phase measurement between a low-atten uation reference material and the sample. The Young's modulus of the s ample is calculated from the displacement amplitude of the sample rela tive to the displacement amplitude of the reference material. Use of t his instrument has allowed the investigation of the dependence of a ro ck's attenuation and Young's modulus on its fluid content. (C) 1996 Am erican Institute of Physics.