My purpose in this commentary is to provide further context to Christensen (2026) in this issue of Seismica in order to fill some gaps so that readers better understand how the measurements are made, know what the analyses are based on, and know where the pitfalls in employing these results might lie. My experiences in reviewing and editing have revealed that many papers that focus on elastic or seismic anisotropy err as they are written often without understanding the basic principles. This problem is aggravated because some modern methods, such as Electron Backscatter Diffraction (EBSD), have made calculation of the anisotropy of metamorphic rocks readily accessible and production of figures perhaps too easy. I hope to both amplify and clarify the results archived in Christensen (2026) so they are not similarly misused and to provide readers with some tutorial background and more in-depth sources in order that they can avoid overinterpretation of anisotropy results more generally.
Douglas R. Schmitt (Sun,) studied this question.