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Detailed Reference Information |
Liu, C. and Ahrens, T.J. (1997). Stress wave attenuation in shock-damaged rock. Journal of Geophysical Research 102: doi: 10.1029/96JB03891. issn: 0148-0227. |
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The velocity and attenuation of ultrasonic stress waves in gabbroic rock samples (San Marcos, California) subjected to shock loading in the 2 GPa range were studied. From P wave velocity measurements we determined the damage parameter Dp and crack density &egr; of the samples and related these to the attenuation coefficient (quality factor) under dynamic strains of 2¿10-7 and at a frequency of 2 MHz using the ultrasonic pulse-echo method. A fit to the data yields the P wave spatial attenuation coefficient at a frequency of 2 MHz, αp(Dp)=1.1+28.2Dp (decibels per centimeter). From the relation between the attenuation coefficient and quality factor, the quality factor Q is given by Q-1=0.011(1+25.6Dp)(1-Dp)1/2. Using O'Connell-Budiansky theory relating crack density to velocity, the parameter in Walsh's theory was determined based on experimental data. An approximate method is also proposed to estimate the average half-length of cracks based on the attenuation measurements.¿ 1997 American Geophysical Union |
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Abstract |
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Keywords
Physical Properties of Rocks, Wave attenuation, Physical Properties of Rocks, Fracture and flow |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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