Implications of the eruptive behavior based on volcanic ash emitted during the 2015 activity of the Cotopaxi volcano, Ecuador

Abstract

The glacial-peaked Cotopaxi stratovolcano in Central Ecuador became visibly active in 2015 for a duration of 101 days, when due to hydrothermal event significant amounts of volcanic particles together with gases precipitated in its surrounding. A detailed day-by-day sampling of these ash particles has led to a thorough morphological, mineralogical and geochemical evaluation in order to characterize the origin and the behavior of the volcano. The mostly trachy-andesitic samples lacked of juvenile material. All evaluated particles, minerals and lithics are of sharp, angular to subangular shapes. Discrimination diagrams and geochemical analysis evidenced a negative correlation between silica (SiO2) and sulfur (SO3), particularly on stronger eruptive occasions. The current study may serve for a general public awareness of volcanic behavior, as the results are able to evaluate and characterize the uprising degree of volcanic explosivity and range of associated hazards in this and similar volcanoes worldwide. Therefore, an immediate evaluation of such volcanic material will be able to result in calming the authorities and the public alike, allowing to offer an additional but decisive tool in the vigilancerestless volcanoes.