Seismic Investigation of the Ojos del Salado Volcano, Chile: The Highest Altitude Volcano in the World

The Ojos del Salado Volcano in Chile is the highest altitude volcano in the world, but has not been visibly active since 1993, when steam was observed rising from near the summit. Since then the volcano has been considered dormant, however, it is unclear if it could become active again, and if so, what the ramifications would be. Little is known about the size and structure of the magma chamber, or its potential interaction with hydrothermal fluids and whether this is the heat source of the nearby hydrothermal lake, Laguna Verde.The region surrounding the volcano is very arid, but due to the cold climate at such high-altitude there are some remnant glaciers and permafrost from the last glacial maximum. Summer meltwater from these cryosphere features contributes to the water budget of the valley below, which adds to the importance of understanding the extent of remaining permafrost and the interactions between local volcanism and the cryosphere that could increase the rate of melting.In this study we combine InSAR data with local seismicity to investigate local crustal deformation and seismic activity at the Ojos del Salado Volcano. A small seismic array, deployed in 2022, measured seismicity in the vicinity of the volcano and acted as a pilot for the 2024 campaign and network design. A dense network of geophones was deployed on the volcano’s flanks in early 2024. We present the first results of the analysis of the data from this denser network, and the pilot study, which already showed seismicity in the vicinity of the volcano. From this analysis we gain insight into the level of activity of the Ojos del Salado Volcano, local deformation patterns and the style of faulting which is also an indication of potential fluid pathways that could link the volcano to the hydrothermal lake. With this information we can better understand the interaction between this unique volcano and the local cryosphere.