Structurally Controlled P-wave Velocity Anisotropy in Oklahoma’s Crystalline Basement: Preliminary Results from an Outcrop Study, Mill Creek, OK1_SSA_2022_Jean_Joel_Legre AGU_2023 EGU_and_SSA_ 2024 SAGE_GAGE_and_SSW_2022 GRC_2025_Jean_Joel_Legre CIG_2025_Jean_Joel_Legre