  Up-going and Horizontal Tau Air-Showers, UpTaus and HorTaus, may trace Ultra
High Energy Neutrino Tau Earth Skimming at the edge of the horizons. Their
secondaries muon, electron pairs, and gamma bundles flashes might trace their
nature over UHECR secondaries in horizontal showers. Indeed the atmosphere act
as a perfect amplifier as well as a filter for showers: down-ward and
horizontal muon bundles may still be originated by far Ultra High Energy Cosmic
Rays skimming the terrestrial atmosphere but their rich gamma component will be
exponentially suppressed. At large zenith angles after crossing a large slant
depth X > 3 10^3 g cm^-2 the number of muons and secondary gamma (produced by
the electron pair from muon decay in flight) is comparable. On the other hand,
up-ward muon bundles from UpTaus and HorTaus may arise within a young shower
with a larger gamma-muon ratio 10^2, leaving a characteristic imprint. We
estimate the UpTaus and HorTaus rate from the Earth and we evaluate the
consequent event rate of muons, electrons pairs andgamma bundles. We show that
such events even for minimal GZK neutrino fluxes could be detected by
scintillator arrays placed on mountains at 1-5km and pointing to the horizon.
The required arrayareas are within tens-hundreds of square meters. The ideal
structure is an array of crown-like twin detectors facing the horizons. We
argue that such detectors will be able to detect both muonic bundles at a
minimal average flux of 10^-11 cm-2 s^-1 sr^-1 and electromagnetic particles
gamma and electron pairs 3 10^-9 cm^-2 s^-1 sr^-1, a few times each year for
GZK neutrino fluxes.

Astrophysics;High Energy Physics - Experiment;High Energy Physics - Phenomenology