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Attenuation of P-Waves by Wave-Induced Fluid Flow.

DE200515013446

Publication Date	2002
Personal Author	Pride, S. R.; Berryman, J. G.
Page Count	14
Abstract	Analytical expressions for three P-wave attenuation mechanisms in rocks are given and numerically compared. The mechanisms are: (1) Biot loss, in which flow occurs at the scale of the wavelength between the peaks and troughs of a P wave; (2) squirt loss, in which flow occurs at the grain scale between microcracks the grains and the adjacent pores; and (3) mesoscopic loss, in which flow occurs at intermediate scales between the various lithological bodies that are present in an averaging volume of earth material. Each mechanism is of importance over different frequency bands. Typically, Biot loss is only important at the highest of ultrasonic frequencies (> 1 MHz), squirt-loss (when it occurs) is important in the range of 10 kHz to 1 MHz, while mesoscale loss dominates at the lower frequencies (<10 kHz) employed in seismology.
Keywords	Rocks Comparisons Numerical analysis Frequency bands Analytical expressions P-wave attenuation Biot loss Squirt loss Mesoscopic loss
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200524

Attenuation of P-Waves by Wave-Induced Fluid Flow.

Attenuation of P-Waves by Wave-Induced Fluid Flow.
DE200515013446

Publication Date	2002
Personal Author	Pride, S. R.; Berryman, J. G.
Page Count	14
Abstract	Analytical expressions for three P-wave attenuation mechanisms in rocks are given and numerically compared. The mechanisms are: (1) Biot loss, in which flow occurs at the scale of the wavelength between the peaks and troughs of a P wave; (2) squirt loss, in which flow occurs at the grain scale between microcracks the grains and the adjacent pores; and (3) mesoscopic loss, in which flow occurs at intermediate scales between the various lithological bodies that are present in an averaging volume of earth material. Each mechanism is of importance over different frequency bands. Typically, Biot loss is only important at the highest of ultrasonic frequencies (> 1 MHz), squirt-loss (when it occurs) is important in the range of 10 kHz to 1 MHz, while mesoscale loss dominates at the lower frequencies (<10 kHz) employed in seismology.
Keywords	Rocks Comparisons Numerical analysis Frequency bands Analytical expressions P-wave attenuation Biot loss Squirt loss Mesoscopic loss
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200524