Galeras Volcano internal structure characterization using geological and geophysics techniques as input to muon tomography studies*

The Galeras Volcano (GV) activity has been monitored for several years due to it is surrounded by highly populated areas. Many populations have grown and settled in dangerous areas, this has increased the risk levels of these populations taking into account the GV recent history of eruptions and generation of pyroclastic flows. In this work, densities in the GV Complex and its variations were analyzed using geological studies and different geophysical methods, such as the seismic tomography of the P wave velocities and gravimetry. In the first method, layers are used at depths ranging from 4 to -10 km, taking 0 km as the sea level. It was obtained that the greatest density variation is between 2 and 0 Km with values between 2.16 and 2.43 g/cm³. Using the gravimetric method, a distribution map of densities ranging from 2.16 to 2.72 g/cm³ was obtained, the map shows a large number of low densities that can correspond to young bodies with little consolidation. The results obtained in this work will be a key input to enhance the developed GEANT4 simulations of GV within the project that aims to study the GV structure using the muon tomography technique.