2010 – 2016 geodetic monitoring of Nevado del Ruiz, Colombia

Nevado del Ruiz volcano is part of a 50 kilometer chain of volcanoes aligned N-S along the Colombian Central Cordillera. Due to its past eruptive history (i.e., the Armero tragedy in 1985), studying this volcanic complex using ground deformation data has considerable value for understanding the physical processes controlling its behavior. Furthermore, this information is essential for reducing the volcanic risk in the region. The deformation of Nevado del Ruiz has been monitored since 1985 and recently the geodetic network has been enhanced with electronic tiltmeters (since 2007) and permanent GNSS stations (since 2011). The monitoring record shows that Nevado del Ruiz has been continuously active since 2010, including an increase in seismicity, large gas and ash emissions, deformation, and moderate explosive eruptions (VEI = 2) such as those in May and June 2012. Analyzing and modeling the time-series from the GPS network allows us to trace the evolution of the deformation trend of Nevado del Ruiz. . Specifically, analysis of GPS and tilt recorded between 2007 and 2012 suggested the migration of magma from a deep reservoir to a shallower one, which is the source of the present unrest. In this work, we present the complete GPS time series from 2010 to the present. This longer data set enabled to study the evolution of the deformation infer the changes in the volume and depth of the magma reservoirs and instigating the unrest. Comparison with seismic and tilt data ensures a further check on the validity of the interpretation of the existing models of unrest, will help in forecasting eruptions and estimating the volcanic hazard in this area.