DOI: 10.5061/dryad.98sf7m0jn
title: Supplemental dataset from: Initial acoustoelastic measurements in olivine: Investigating the effect of stress on P- and S-wave velocities

description: It is well known that elasticity is a key physical property in the
 determination of the structure and composition of the Earth and provides
 critical information for the interpretation of seismic data. This study
 investigates the stress-induced variation in elastic wave velocities,
 known as the acoustoelastic effect, in San Carlos olivine. A recently
 developed experimental ultrasonic acoustic system, the Directly Integrated
 Acoustic System Combined with Pressure Experiments (DIASCoPE), was used
 with the D-DIA multi-anvil apparatus to transmit ultrasonic sound waves
 and collect the reflections. We use the DIASCoPE to obtain longitudinal
 (P) and shear (S) elastic wave velocities from the sample which we compare
 to our known stress state in the D-DIA derived from synchrotron X-ray
 diffraction. We use elastic-plastic self-consistent (EPSC) numerical
 modeling to forward model X-ray diffraction data collected in D-DIA
 experiments to obtain the macroscopic stress on our sample. We can observe
 the relationship between the relative elastic wave velocity change (ΔV/V)
 and macroscopic stress to determine the acoustoelastic constants, and
 interpret our observations using the linearized first-order equation based
 on the model proposed by Hughes and Kelly (1953). This work supports the
 presence of the acoustoelastic effect in San Carlos olivine, which can be
 measured as a function of pressure and temperature. This study will aid in
 our understanding of the acoustoelastic effect and provide a new
 experimental technique to measure the stress state in elastically deformed
 geologic materials at high pressure conditions.
description: The ultrasonics-modified deformation-DIA experiments were
 conducted using the D-DIA multi-anvil apparatus (Durham et al., 2002) and
 DIASCoPE acoustic system (Whitaker et al., 2017) located at the 6-BM-B
 beamline at the Advanced Photon Source at Argonne National Laboratory,
 Chicago, Illinois. The D-DIA multi-anvil apparatus combined with a
 synchrotron beamline provides the ability to measure sample stress and
 strain using in-situ X-ray techniques during the deformation experiment.
 The incorporation of the DIASCoPE acoustic system into a traditional D-DIA
 experiment allowed for simultaneous travel time measurements when
 deforming. Using the sample length measurements from synchrotron
 X-radiographic imaging and P- and S-wave travel times from the DIASCoPE,
 the elastic P- and S-wave velocities were determined. We peak fit
 diffraction data from the compressional (ψ= 0°, 180°) and transverse
 detectors (ψ= 90°) using Plot85. The olivine diffraction peaks measured to
 obtain d-spacing values were (130), (131), (112), (122), (140), and (211).
 Powder diffraction data collected from the sample during deformation was
 then interpreted through elastic-plastic self-consistent (EPSC) modeling
 (Tomé & Oliver, 2002) following the strategies devised by Burnley
 (2015) and Burnley and Kaboli (2019) to determine the macroscopic stress
 on the sample.