Theory and Practice: Techniques for Measuring High-P-T Elasticity

This chapter reviews many of the most commonly used experimental methods for measuring the elastic properties and sound velocities of the Earth and planetary materials. The basic principles underlying different techniques are presented, along with some of the strengths and limitations of each type of measurement at the present time. Emphasis is placed on experimental methods that have been adapted for use under high-pressure and high-temperature conditions, making them extremely important for understanding the deep Earth and planetary interiors. The development of more intense synchrotron x-ray sources now allows measurements with very high energy resolution and has greatly expanded the range of techniques available for the determination of elastic properties under extreme pressure-temperature conditions. These recent developments are summarized along with the types of pressure-generating devices used in modern elasticity research.