  The origin and nature of ultrahigh-energy cosmic ray events, above the
Greisen-Zatsepin-Kuzmin (GZK) cutoff energy, constitute a long-standing,
unsolved mistery. Neutrinos are proposed candidates but their standard
interactions with matter are too weak. In the context of a TeV-scale string
theory, motivated by possible extra space dimensions, the neutrino-nucleon
scattering is examined. Resonant string contributions increase substantially
the standard model neutrino-nucleon cross section. Although they seem
insufficient to explain the trans-GZK cosmic ray events, their effects might be
detected in next experiments.
