Open AccessAttenuation behaviour of tuffaceous sandstone and granite during microfracturing
Author(s) -
Wulff AngelikaM.,
Hashida Toshiyuki,
Watanabe Kimio,
Takahashi Hideaki
Publication year - 1999
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1046/j.1365-246x.1999.00943.x
Subject(s) - attenuation , geology , mineralogy , seismic wave , seismology , rayleigh wave , rayleigh scattering , scattering , geotechnical engineering , wave propagation , optics , physics
Laboratory measurements of ultrasonic wave propagation in tuffaceous sandstone (Kimachi, Japan) and granite (Iidate, Japan) were performed during increasing fracturing of the samples. The fracturing was achieved by unconfined uniaxial compression up to and beyond the point of macrofracture of the specimen using a constant low strain rate. The observed variation of wave velocity (up to 40 per cent) due to the development of micro‐ and macrofractures in the rock is interpreted by rock models relating velocity changes to damage and crack density. The calculated density of the newly formed cracks reaches higher values for the sandstone than for the granite. Using the estimated crack densities, the attenuation behaviour is interpreted in terms of different attenuation mechanisms; that is, friction and scattering. Rayleigh scattering as described by the model of Hudson (1981) may explain the attenuation qualitatively if the largest plausible crack dimensions are assumed in modelling.