Possible tau appearance experiment with atmospheric neutrinos

We suggest an experimental measurement that could detect the appearance of the tau neutrinos in muon to tau neutrino oscillations of atmospheric neutrinos by measuring the energy spectra of neutrino induced showers. Tau neutrinos deposit a large fraction of their energy in showers generated in CC interactions and the subsequent tau--lepton decay. The appearance of tau neutrinos will enhance the spectrum of neutrino induced showers in energy ranges corresponding to the neutrino oscillation parameters. A shower rate lower than the `no oscillation' prediction is an indication for oscillations into sterile neutrinos.