Resolution of the ANITA Upward Air Shower Anomaly: Substrate Surface Shear Waveguiding, Interface Dielectric Transition Cleavage, and the Elimination of Trans-Earth EeV Neutrino Transport

The Antarctic Impulsive Transient Antenna (ANITA) during the ANITA-I and ANITA-III flights detected anomalous upward-directed extensive air showers emerging from the ice sheet at steep angles (θ = -27.4° and -35.0°) with energies E ~ 0.6 EeV. Crucially, their horizontal radio polarization showed zero phase inversion, firmly excluding direct cosmic-ray reflection from the ice surface. In standard particle physics, interpreting these signals as tau neutrino (ν_τ) interactions requires trans-Earth chord penetration of ~6000–7000 km. However, the EeV neutrino-nucleon cross-section restricts the terrestrial absorption mean free path to L_mfp ≤ 200–300 km, reducing the survival probability to P_surv ≤ 10^-24. Furthermore, null detections from IceCube and the Pierre Auger Observatory exclude diffuse EeV flux models by four orders of magnitude, forcing orthodox physics into fine-tuned BSM scenarios. Building upon our foundational series on the physical vacuum as an elastically pre-stressed continuum, we show that the ANITA events are an interface elastodynamic phenomenon rather than trans-Earth particle transport. In our ontology, space is an elastically pre-stressed medium with holding pressure P_0 ≈ 7.48 × 10^24 Pa and shear modulus G_v = P_0. Glancing ultra-high-energy cosmic-ray solitons incident near the horizon excite localized transverse acoustic shear modes trapped within the shallow Antarctic firn waveguide by the positive vertical refractive index gradient (dn/dz > 0). When these horizontally guided modes encounter local sub-surface glacial slopes, they undergo coherent dielectric transition cleavage into the atmosphere. Because the wave transmits from a denser medium into air, the Fresnel transmission coefficient is strictly positive (t_perp > 0), naturally reproducing the observed non-inverted phase (Δφ = 0°) and exit angles without requiring trans-Earth particle survival.