Relationship Between Deformation and Explosive Eruptions at Rincón de la Vieja Volcano, Costa Rica Detected Using GNSS
Emily Mick1, Cyril Muller2, and John Stix1
Affiliations: 1McGill University, Earth and Planetary Science, Canada 2Observatorio Volcanológico y Sismológico de Costa Rica (OVSICORI), Costa Rica
Presentation type: Talk
Presentation time: Friday 09:15 - 09:30, Room R380
Programme No: 2.3.4
Abstract
Rincón de la Vieja volcano is a highly active volcano hosting a complex magmatic-hydrothermal system and between July 2021 and December 2023 experienced hundreds of phreatic and phreatomagmatic eruptions. Volcanic deformation typically focuses on magmatic systems where inflation due to magma injection is an important indicator of potential eruptive activity. Meanwhile, phreatic eruptions due to the sudden flashing of trapped water without the eruption of magma result in deformation is at a much smaller scale. This study finds that multiple scales of deformation are occurring at Rincón. A GNSS network set up and maintained by OVSICORI includes stations located 1 km southwest, 5 km northwest, 6 km northeast and 5 km southwest of the active vent. Periods of long-term inflation were detected between January and June 2022 (6 months) as well as between December 2022 and November 2023 (11 months). These periods resulted in up to 32 mm and 40 mm of inflation respectively which modelling indicates is the result of a deep magma body 7-11 km below the vent. Additionally, these windows are associated with periods of significant eruptive activity. Before, during and after these periods, shorter periods of inflation lasting 20 to 40 days occur resulting in up to 30 mm of inflation resulting from pressurization of a source within the shallow (1-1.5 km below the vent) hydrothermal system. These findings indicate that several processes, shallow hydrothermal and deeper magmatic, are occurring at times sequentially or simultaneously to produce the observed deformation and eruptive activity at Rincón.