  We have studied the Earth matter effect on the oscillation of upward going
GeV neutrinos by taking into account the three active neutrino flavors. For
neutrino energy in the range 3 to 12 GeV we observed three distinct resonant
peaks for the oscillation process $\nu_e\leftrightarrow \nu_{\mu,\tau}$ in
three \textit{distinct} densities. However, according to the most realistic
density profile of the Earth, the second peak at neutrino energy 6.18 GeV
corresponding to the density $6.6\,g/cm^3$ does not exist. So the resonance at
this energy can not be of MSW-type. For the calculation of observed flux of
these GeV neutrinos on Earth, we considered two different flux ratios at the
source, the standard scenario with the flux ratio $1:2:0$ and the muon damped
scenario with $0:1:0$. It is observed that at the detector while the standard
scenario gives the observed flux ratio $1:1:1$, the muon damped scenario has a
different ratio. For muon damped case with $E_{\nu} < 20$ GeV, we always get
observed neutrino fluxes as $\Phi_{\nu_e} < \Phi_{\nu_\mu}\simeq
\Phi_{\nu_\tau}$ and for $E_{\nu} > 20$ GeV, we get the average
$\Phi_{\nu_e}\sim 0$ and $\Phi_{\nu_\mu}\simeq \Phi_{\nu_\tau}\simeq 0.45$. The
upcoming PINGU will be able to shed more light on the nature of the resonance
in these GeV neutrinos and hopefully will also be able to discriminate among
different processes of neutrino production at the source in GeV energy range.
