Understanding the properties of magmatic plumbing systems beneath active volcanoes is crucial to better characterise volcanic processes at both local and global scales. Locally, this helps identify crustal reservoirs, determine magma supply rates, and map migration processes throughout the eruptive cycle – information that directly informs our scientific understanding of volcanic processes, improves volcanic-hazard mapping, and supports the development and management of geothermal resources. Globally, such insights improve our understanding of how these systems interact within the solid Earth, oceans, and atmosphere.

Despite its importance, directly measuring the Earth’s subsurface remains a challenge. Deformation measurements from Interferometric Synthetic Aperture Radar (InSAR) and subsequent geophysical modelling offer potential solutions, but have limitations related to resolution and uncertainties in estimating the geometry, depth, and volume change of magma sources. In addition, estimates of elastic and rheological properties are often lacking and rely on unverified assumptions.

To overcome these challenges, this study introduces an interdisciplinary approach, leveraging the integrated strengths of seismic and geodetic space-time metrics and using Icelandic volcanoes as case studies. The objectives of this study are as follows: (i) derive phase velocities from seismic ambient noise using seismic interferometry to enhance 3D shear-wave tomography of volcanic structures; (ii) estimate InSAR-derived time series to model surface deformation and provide estimates for the geometry, depth, and volumechanges ofmagmatic plumbing systems, incorporating seismic or other geodetic constraints whenever possible; and (iii) assess the effectiveness of the above-mentioned methods using real and simulated…