INSAR ANALYSIS OF THE RINCÓN DE LA VIEJA VOLCANO: EXPLORING THE RELATIONSHIP BETWEEN GROUND DISPLACEMENT AND ERUPTIVE ACTIVITY

The Guanacaste Volcanic Cordillera(GVC) in Costa Rica is a well-monitored range that provides opportunities to analyze eruption dynamics and volcanic hazards in an area with critical national infrastructure. Rincón de la Vieja is an andesitic, composite volcano that has been active since 2011, with numerous phreatic events occurring every few months. Various communities and the state-owned Borinquen-Las Pailas geothermal plant are within a few kilometers of the active crater. Assessing the hazards posed by Rincón de la Vieja to these communities are essential. The seismic and volcanic activity at Rincón is well monitored and has ideal conditions for InSAR (Interferometric Synthetic Aperture Radar) studies as it is less vegetated than other surrounding volcanic centers. From January 2020 to May 2023, velocity time series analyses of 122 Sentinel-1 images reveal substantial fluctuations— as great as 25mm within a 12-day span— in the phase range within the line of sight. Comparisons with Real-Time Energy Measurements (RSEM) from the VRBA station at Rincón, reveal that the most energetic eruptive events coincide with periods of ground subsidence relative to the satellite, and are preceded by periods of significant uplift towards the satellite. This method of estimating ground deformation using InSAR, can provide new data as frequently as every 12 days, which can prove to be an invaluable method for monitoring and hazard mitigation.