scholarly journals Grain shape and sorting effects on the frequency dependence of shear wave attenuation in water saturated sediments

1981 ◽  
Vol 69 (S1) ◽  
pp. S96-S96
Author(s):  
Burlie A. Brunson ◽  
James E. Matthews
Keyword(s):  
Frequency Dependence ◽  
Shear Wave ◽  
Grain Shape ◽  
Wave Attenuation ◽  
Water Saturated

Effects of fluid viscosity on shear‐wave attenuation in saturated sandstones

Geophysics ◽  
1990 ◽  
Vol 55 (6) ◽  
pp. 712-722 ◽  
Author(s):  
D. Vo‐Thanh
Keyword(s):  
Shear Wave ◽  
Wave Attenuation ◽  
Crack Density ◽  
Viscoelastic Model ◽  
Fluid Viscosity ◽  
Partially Saturated ◽  
Aspect Ratios ◽  
Viscous Shear ◽  
Shear Relaxation ◽  
Water Saturated

Measurements of shear wave velocity and attenuation as a function of temperature were made in the kilohertz frequency range in sandstones saturated with various liquids. For sandstones partially saturated with glycerol, two attenuation peaks are observed between −80°C and 100°C; they are attributed to viscous shear relaxation and squirt flow. For fully water‐saturated Berea sandstone, the attenuation decreases as the crack density increases. The displacement of the squirt peak, caused by the increase of the central aspect ratio of cracks, is at the origin of this decrease. A simple viscoelastic model, based on the model of O’Connell and Budiansky using a Cole‐Cole distribution of cracks, is proposed for calculation of the shear modulus of fluid‐saturated rocks. This model interprets the experimental data satisfactorily. The data suggest that the shear attenuation and velocity are controlled by the distribution of crack aspect ratios.

scholarly journals Lorentz force induced shear waves for magnetic resonance elastography applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guillaume Flé ◽  
Guillaume Gilbert ◽  
Pol Grasland-Mongrain ◽  
Guy Cloutier
Keyword(s):  
Magnetic Resonance ◽  
Shear Wave ◽  
Lorentz Force ◽  
Wave Attenuation ◽  
Shear Waves ◽  
Estimation Method ◽  
Biological Tissues ◽  
Magnetic Resonance Elastography ◽  
Motion Generation ◽  
Wave Source

AbstractQuantitative mechanical properties of biological tissues can be mapped using the shear wave elastography technique. This technology has demonstrated a great potential in various organs but shows a limit due to wave attenuation in biological tissues. An option to overcome the inherent loss in shear wave magnitude along the propagation pathway may be to stimulate tissues closer to regions of interest using alternative motion generation techniques. The present study investigated the feasibility of generating shear waves by applying a Lorentz force directly to tissue mimicking samples for magnetic resonance elastography applications. This was done by combining an electrical current with the strong magnetic field of a clinical MRI scanner. The Local Frequency Estimation method was used to assess the real value of the shear modulus of tested phantoms from Lorentz force induced motion. Finite elements modeling of reported experiments showed a consistent behavior but featured wavelengths larger than measured ones. Results suggest the feasibility of a magnetic resonance elastography technique based on the Lorentz force to produce an shear wave source.

scholarly journals Imaging of shear wave attenuation along the central part of the North Anatolian Fault Zone, Turkey

2019 ◽  
Vol 23 (4) ◽  
pp. 913-927 ◽  
Author(s):  
Peter Gaebler ◽  
Tuna Eken ◽  
Hüseyin Önder Bektaş ◽  
Tom Eulenfeld ◽  
Ulrich Wegler ◽  
...  
Keyword(s):  
Shear Wave ◽  
Fault Zone ◽  
Wave Attenuation ◽  
North Anatolian Fault ◽  
North Anatolian Fault Zone ◽  
The North
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