Volcanic connections
Magmatic connectivity among six Galápagos volcanoes revealed by satellite geodesy
Bartolomé Island, Galápagos. Satellite data reveal correlated displacement of several Galápagos volcanoes during periods of magmatic unrest
Constraining the subsurface behaviour of magma using surface observations is notoriously difficult. At oceanic hotspots, the crust is relatively thin, which facilitates frequent effusive activity, shallow magma storage, and multiple pathways for magma ascent. This makes volcanoes associated with oceanic hotspots useful candidates for understanding magmatic systems, by conducting geochemical analyses on recently erupted material or monitoring surface deformation.
Eoin Reddin at the University of Leeds, UK, and colleagues use radar data from the Sentinel-1 satellite to study volcanic displacement in the Western Galápagos, where six active volcanoes lie atop oceanic crust and within 30-45 km of each other. Using Interferometric Synthetic Aperture Radar (InSAR) data, the team studied displacement across the volcanoes from January 2017 to March 2022, during which time five eruptions occurred.
The team analysed approximately 2,000 interferograms and showed that there was a correlation between deformation at all six volcanoes and eruptive activity and elevated magma flux. No magmatic or tectonic events during the period of study were sufficiently large or long-lasting to account for these correlations. The team instead conclude that the studied volcanoes may have an interconnected magmatic system where changes in magma supply affect the entire system – connectivity at the base of the crust would be consistent with petrological evidence from other studies.
The study shows that volcanic displacement measured using satellite data can be used to constrain the nature of magma storage and transportation up to several kilometres deep into the crust. While this analysis focuses on the Western Galápagos, the approach could be applied to other oceanic hotspots, such as Ascension, Cape Verde, or Réunion. The study also highlights the importance of regular, temporally dense data points, as the authors argue that these were key for adequately analysing volcanic deformation in the Western Galápagos.
Marissa Lo
Details
Nat. Comm. 14, 6614 (2023); doi.org/10.1038/s41467-023-42157-x
