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.