Inversion for weak triclinic anisotropy from acoustic axes

► Directions of acoustic axes can be inverted for elastic anisotropy. ► The maximum number of acoustic axes in triclinic anisotropy is 16. ► The minimum number of acoustic axes which can be inverted is 7. ► The inversion yields 13 anisotropy parameters. ► The rest of anisotropy parameters must be inverted from other attributes of waves.