Complex paths of magma propagation at Fernandina (Galápagos): The coexistence of circumferential and radial dike intrusion during the January 2020 eruption

Abstract

Understanding paths of magma propagation is fundamental to infer how magma could propagate in future volcanic eruptions. Here I studied the 2020 circumferential eruption occurred on the east ank of Fernandina volcano (Galápagos), using Interferometric Synthetic Aperture Radar (InSAR) data and geodetic modelling. Results show that a radial dike propagated southward, possibly triggering a submarine eruption, changing its geometry at each topographic change. No deformation matches in location with the circumferential eruptive ssures, likely associated with an ephemeral circumferential dike that have shared with the radial dike the same intra-caldera intruded sill. This eruption is the rst documented event in Galápagos where circumferential and radial dikes occur simultaneously, suggesting that magma in these volcanoes can also propagate from the same intrusion in opposite directions, with different geometries. The volume lost by the deep reservoir mainly owed in the radial dike, potentially explaining why the eruption lasted for 9 hours only.