Plastic yielding as a frequency and amplitude independent mechanism of seismic wave attenuation

Details

Serval ID
serval:BIB_D60BF6678A4D
Type
Article: article from journal or magazin.
Collection
Publications
Title
Plastic yielding as a frequency and amplitude independent mechanism of seismic wave attenuation
Journal
Geophysics
Author(s)
Yarushina V.M., Podladchikov Y.Y.
ISSN-L
0016-8033
Publication state
Published
Issued date
2010
Peer-reviewed
Oui
Volume
75
Pages
N51-N63
Language
english
Abstract
We have developed a mathematical formulation of two mechanisms of
compressional wave attenuation, which can occur within the solid rock
frame prestressed up to its yield stress in part of its volume. Energy
losses are attributed to two distinct processes: irreversible plastic
yielding and formation of radial microfractures around microscopic
cavities. Small-amplitude waves propagating through the rocks
prestressed at their yield point would cause nonelastic strain to avoid
building local stresses above the yield limit and attenuate some
fraction of their energy per every loading cycle. New mechanisms of
microscale yielding and microfracturing give rise to
frequency-independent attenuation due to rate-independence of plasticity
formulation. Quality factor Q predicted by the model is independent of
strain amplitude for small strains and decreases with increasing
amplitude for large strains. We found that attenuation can be high even
for small seismic strains (10(-9)-10(-5)). Thus, Q = 12...20 is achieved
at effective pressures greater than twice the yield strength of the
solid matrix for the plastic yielding mechanism and at overpressures
exceeding half tensile strength for microfracturing.
Create date
09/10/2012 19:50
Last modification date
20/08/2019 15:55
Usage data