Magma conduit-induced ground deformation at lava dome–building volcanoes

Monitoring ground deformation induced by magma conduits at lava dome–building volcanoes provides key insights into magma ascent dynamics. Changes in dome growth rate are often associated with hazards such as increased explosive activity, dome collapse events, and pyroclastic flows. Timely detection and interpretation of precursory unrest are therefore vital for hazard assessment. 

This study aims to elucidate the range of detectable conduit processes, inform the deployment of ground deformation monitoring infrastructure, and identify which conduit processes meet the detection criteria for measurement using high-resolution InSAR. We use 2D axisymmetric physics-based fluid dynamic models of magma ascent coupled to an elastic edifice to demonstrate how variations in shear stress and excess pressure on conduit boundaries generate ground deformation proximal to growing domes. Model scenarios are compared for three recent lava dome eruptions, highlighting key parameters controlling conduit-induced deformation, including syn-eruptive crystallisation, outgassing, initial conduit geometry, and magma composition. 

The potentially long-lived and periodic nature of lava dome eruptions enables strategic deployment of ground-based monitoring infrastructure, such as tiltmeters, to improve observation of such events. This study provides a framework for assessing which transitions in conduit behaviour may be detectable, and over what distances from the conduit, by different geodetic methods.