The Use of Ultrasonic Measurements Under Modest Compression to Estimate Compression at High Pressure
- Thomas J. Shankland and
- Jay D. Bass
Published Online: 21 MAR 2013
Copyright 1988 by the American Geophysical Union.
Elastic Properties and Equations of State
How to Cite
Anderson, O. L. (1988) The Use of Ultrasonic Measurements Under Modest Compression to Estimate Compression at High Pressure, in Elastic Properties and Equations of State (eds T. J. Shankland and J. D. Bass), American Geophysical Union, Washington, D. C.. doi: 10.1029/SP026p0134
- Published Online: 21 MAR 2013
- Published Print: 1 JAN 1988
Print ISBN: 9780875902401
Online ISBN: 9781118664971
- Adiabatic-isothermal transformations;
- Logarithmic compression equation;
- Polynomial compression equation;
- Thermal expansivity data;
- Ultrasonic measurements
The variation of sound velocities with pressure can be measured by ultrasonic techniques with great precision, but the pressure range is limited. It is shown how such measurements can be used to estimate the volume dependence on pressure, or compression V/V 0, at pressures one or two orders of magnitude higher than the pressure of the velocity measurements.
A formula for the compression is presented which is based upon the assumption that the bulk modulus is linear with pressure. The parameters of this formula are evaluated with acoustic data so that there are no arbitrary constants or ‘curve-fitting'. The compression formula is compared with polynomial approximations to it and with an equation due to Birch. The compression is evaluated for 14 compounds including compressible materials like K, incompressible materials like Al2O3, and hexagonal metals like Cd. The agreement between the formula and experimental compression data is satisfactory to 100 or 200 kbar, and in several cases to over 1000 kbar.