Nonlinear Attenuation Effects Outside the Zone of Macroscopic Failure

  1. Steven R. Taylor,
  2. Howard J. Patton and
  3. Paul G. Richards
  1. Brian P. Bonner and
  2. B. J. Wanamaker

Published Online: 18 MAR 2013

DOI: 10.1029/GM065p0091

Explosion Source Phenomenology

Explosion Source Phenomenology

How to Cite

Bonner, B. P. and Wanamaker, B. J. (1991) Nonlinear Attenuation Effects Outside the Zone of Macroscopic Failure, in Explosion Source Phenomenology (eds S. R. Taylor, H. J. Patton and P. G. Richards), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM065p0091

Author Information

  1. Lawrence Livermore National Laboratory, livermore, California 94550

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1991

ISBN Information

Print ISBN: 9780875900315

Online ISBN: 9781118663820

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Keywords:

  • Underground nuclear explosions—Detection—Congresses;
  • Seismology—Congresses

Summary

Laboratory evidence unambiguously shows that the mechanical response of rock at low confining pressure is nonlinear, meaning that attenuation is strain-amplitude-dependent, for strains between ∼10−6 and those sufficient to cause permanent damage, 10−3 to 10−2. We compare the magnitude of nonlinear attenuation for soils, microscopically cracked granite, and macroscopically fractured granite. A compilation of data for attenuation in soils from the civil engineering literature documents the strong nonlinear response in these materials over the strain range 10−6 to 10−3. Nonlinear soil response would be most important in near surface layers. We show direct evidence that fatigue microcracking resulting from high-frequency and ultrasonic measurement techniques may lead to systematic overestimates of nonlinear attenuation. New data for attenuation due to sliding on a single macrofracture in granite shows that large attenuation (up to Q−1 = 0.1) can occur at strains of 5 × 10−4 at low normal stress. Measurable nonlinear response attributable to the fracture persists to strains near 10−6 and to normal stresses corresponding to overburden pressures at typical burial depths for underground explosions.