2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/197283We have previously shown that the decay of high-energy neutrinos from distant astrophysical sources would be revealed by flavor ratios that deviate strongly from the $ϕ_{ν_e}:ϕ_{ν_μ}:ϕ_{ν_τ} = 1:1:1$ expected from oscillations alone. Here we show that the deviations are significantly larger when the mixing angle $θ_{13}$ and the CP phase $δ$ are allowed to be nonzero. If neutrinos decay, this could allow measurement of $θ_{13}$ and $δ$ in IceCube and other near-term neutrino telescopes.3 pages, 3 figures, submitted to PRD Brief ReportsHigh Energy Physics - PhenomenologyAstrophysicstext