Análisis Elemental Semicuantitativo de las Cenizas Volcánicas de las Poblaciones Aledañas al Volcán Tungurahua del Período Eruptivo 2008-2010, Mediante el Uso de Espectroscopía LIBS (Laser-Induced Breakdown Spectroscopy)

Abstract

The geochemical characterization of volcanic ash is of a great scientific interest since it allows to determine the physical conditions of volcanic eruptions. This work applied the LIBS technique in 18 ash samples from the Tungurahua volcano from the 2008-2010 eruptive period. The work proposes suitable preparation methods for volcanic ash to guarantee the homogeneity of the sample and the data obtained. The analysis was carried out in two different environments, common air and atmosphere saturated with argon. For the quantitative analysis Calibration-free LIBS (CF-LIBS) is used, a technique used to determine the elemental composition of an arbitrary sample by statistical distributions of Saha-Boltzmann and Boltzmann without calibration curves. The instrumental response function of the LIBS equipment of the EPN was determined. A comparison was made of the data obtained by CF-LIBS with EDS and with ICP-AES. The concentrations determined with these techniques coincide within the experimental range, and this allowed to define correction factors for the concentrations obtained with CF-LIBS. A list of the chemical elements in ashes of andesitic volcanoes was defined for future analyzes with CF-LIBS.