New images of volcanic systems on the Reykjanes Peninsula, Iceland, from ambient noise tomography using a regional node array

Unrest has been ongoing on the Reykjanes Peninsula, Iceland, since 2019, with inflation in the Fagradalsfjall and Eldvörp-Svartsengi volcanic centres resulting in a series of volcanic eruptions beginning in 2021. We have operated a permanent broadband seismometer network on the peninsula since June 2020, complemented by networks run by several other groups. Recently, these were supplemented by 24 three-component nodes for two months starting in September 2025, which provided improved coverage in the western part of the peninsula, and further enhanced both the spatial footprint and density of the combined arrays.

Using this new dataset, and taking advantage of a period of relative volcanic and seismic quiescence, a new 3D shear wave velocity model for the peninsula is constructed from inter-station surface wave dispersion curves extracted from ambient seismic noise cross-correlations. The dense node deployment also allows analysis of shallow crustal anisotropy, thus helping to pinpoint magmatic storage regions and areas of shallow fractures. The final model spans the shallow crust from the surface to 8 km depth, with lateral model resolution approaching 1 km above the brittle-ductile transition. This allows imaging of the Reykjanes, Fagradalsfjall and Eldvörp-Svartsengi volcanic systems, as well as of geothermal fields on the peninsula.