WIT Press

Laboratory Identification Of The Quality Factor Q: Comparative Presentation And Evaluation Of Spectral Ratio And Rise Time Methods

Price

Free (open access)

Paper DOI

10.2495/SD950471

Volume

15

Pages

8

Published

1995

Size

746 kb

Author(s)

N.S. Klimis

Abstract

Two different methods for evaluating attenuation through the quality factor Q are presented, tested and compared. Both methods are based on laboratory experi- ments of ultrasonic P waves propagation at "ad-hoc" rock samples. The advanta- ges of each experimental method are discussed . The spectral method is a rather laboratory oriented methodology providing attenuation information over a range of frequencies and seems to be well adapted for intermediate attenuative media of propagation. Its outcome is strongly influenced by parasitic signal reflections, cou- pling functions and scattering effects. On the other hand , the rise time method less influenced by scattering phenomena, is dependent on the coupling functions (role of interfaces) and the experimental set-up. For a given

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