Effect of phase transitions on compressional-wave velocities in the Earth’s mantle

Nature ◽  
2008 ◽  
Vol 454 (7207) ◽  
pp. 984-986 ◽  
Author(s):  
Li Li ◽  
Donald J. Weidner
Keyword(s):  
Phase Transitions ◽  
Compressional Wave ◽  
Earth’S Mantle ◽  
Wave Velocities

Compressional‐wave velocities in attenuating media: A laboratory physical model study

Geophysics ◽  
2000 ◽  
Vol 65 (4) ◽  
pp. 1162-1167 ◽  
Author(s):  
Joseph B. Molyneux ◽  
Douglas R. Schmitt
Keyword(s):  
Phase Velocity ◽  
Group Velocity ◽  
Wave Velocity ◽  
Propagation Distance ◽  
Compressional Wave ◽  
Arrival Times ◽  
Wave Velocities ◽  
Amplitude Maximum ◽  
Phase And Group Velocities ◽  
Group Velocities

Elastic‐wave velocities are often determined by picking the time of a certain feature of a propagating pulse, such as the first amplitude maximum. However, attenuation and dispersion conspire to change the shape of a propagating wave, making determination of a physically meaningful velocity problematic. As a consequence, the velocities so determined are not necessarily representative of the material’s intrinsic wave phase and group velocities. These phase and group velocities are found experimentally in a highly attenuating medium consisting of glycerol‐saturated, unconsolidated, random packs of glass beads and quartz sand. Our results show that the quality factor Q varies between 2 and 6 over the useful frequency band in these experiments from ∼200 to 600 kHz. The fundamental velocities are compared to more common and simple velocity estimates. In general, the simpler methods estimate the group velocity at the predominant frequency with a 3% discrepancy but are in poor agreement with the corresponding phase velocity. Wave velocities determined from the time at which the pulse is first detected (signal velocity) differ from the predominant group velocity by up to 12%. At best, the onset wave velocity arguably provides a lower bound for the high‐frequency limit of the phase velocity in a material where wave velocity increases with frequency. Each method of time picking, however, is self‐consistent, as indicated by the high quality of linear regressions of observed arrival times versus propagation distance.

Viscosity-depth profile of the Earth's mantle: Effects of polymorphic phase transitions

1977 ◽  
Vol 82 (26) ◽  
pp. 3747-3761 ◽  
Author(s):  
Charles G. Sammis ◽  
John C. Smith ◽  
Gerald Schubert ◽  
David A. Yuen
Keyword(s):  
Phase Transitions ◽  
Depth Profile ◽  
Earth’S Mantle

scholarly journals Compressional Wave Velocities in Eclogites of the Dabieshan, Central China to 5.0GPa: A Preliminary Result.

1998 ◽  
Vol 7 ◽  
pp. 12-14 ◽  
Author(s):  
Zhidan Zhao ◽  
Hongsen Xie ◽  
Wenge Zhou ◽  
Zeming Zhang ◽  
Jie Guo ◽  
...  
Keyword(s):  
Compressional Wave ◽  
Central China ◽  
Wave Velocities

Grain size effect on compressional wave velocities in carbonate rocks under pressure

2021 ◽  
Author(s):  
Jingyi Guo ◽  
Liqin Sang ◽  
Min Li ◽  
Michael C. Pope ◽  
Yuefeng Sun
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Carbonate Rocks ◽  
Compressional Wave ◽  
Grain Size Effect ◽  
Wave Velocities
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