Muon radiography is based on the observation of the absorption of muons in matter, as the ordinary radiography does by using X-rays.
The interaction of cosmic rays with the atmosphere produce Extensive Air Showers (EAS), which provide abundant source of muons. These particles can be used for various applications of muon radiography, in particular to study the internal structure of different volcanoes edifice. We will
focus on Galeras volcano located 9 km from Pasto city (Colombia).

In this work we present the first study of the muon lateral distribution at Pasto altitude (4276 m a.s.l.) and a preliminary simulation the
volcanic cone using GEANT4. For the interaction of the cosmic rays with the atmosphere we have used CORSIKA 74004
software with an atmosphere tropical model and QGSJETII-04 as hadronic model for the high energies and GHEISHA2002d for low energies.
The analysis considers two different primary particle (proton and iron), four zenith angles (0°, 30°, 45° and 60°)
with energies values of 5, 10 and 100 TeV.