Multi-instrumental investigation of volcanic outgassing at Pacaya volcano, Guatemala

Pacaya is one of the most active volcano in the world and it is only ≈30Km South of Guatemala City, the capital of Guatemala, that has a population of about 2 million of people and a surrounding metropolitan area where ≈4.5 million of people live. So mitigate the volcanic hazard improving the knowledge and the understanding of Pacaya is fundamental to decrease the risk factor at which the surrounding population is exposed. This study aims to furnish a new large database, the analysis, the comparison and the interpretations of data that come from different techniques of sampling, about the volcanic outgassing at Pacaya.;A total number of 440 samples were collected with the CO2 accumulation chamber, principally from the northern side of the volcano; about 8000 images were obtained using an UV camera from the foot of Pacaya and about two weeks of seismological data were collected by a seismic station buried nearby the summit of the volcano. The processing of all these data produced the first CO2 efflux map and the first comparison between SO 2 data and seismic data of this volcano; furthermore it gave back to us the emission rate values for both the volcanic gasses. Moreover we mapped a new possible system of faults, in this work called "secondary faults", and, using Google Earth Pro, the opening of a new eruptive fissure on the South-Eastern side of the volcano. We also confirmed the NNW orientation of the magma ascension and that there is a direct relationship between low-frequencies seismic signal and the outgassing of the SO2.;In the last chapter of this study we propose a list of much food for thought for future studies and also solutions and ideas to solve them.