  Strong, anisotropic turbulence reflecting magnetized filaments is considered,
to model the diffusive acceleration of particles by shock waves in active
galactic nucleus jets. We address that at knot A of the nearby M87 jet, the
shock involving the filamentary turbulence can accelerate an iron nucleus to
zetta-eV (ZeV; 10^{21} eV) ranges. A smaller value of the particle diffusion
coefficient is found to be essential to achieve a ZeV cosmic-ray accelerator, a
"Zevatron."
