Fig. 5: Ground deformation and conduit dynamics.
From: Ground deformation reveals the scale-invariant conduit dynamics driving explosive basaltic eruptions
Conceptual model of the pre-eruptive process causing ground inflation lasting 610 s (red line) before the eruptive onset on 3 July 2019 and a the geometrical parameters used to locate the source with the open-conduit model36. In the initial phase (a), gas rising from depth (zo) expands, forcing the magma column towards the surface (b) and leading to a precursory emission of lava outside the vent. Ground deformation is caused by an increase in magmastatic pressure and/or pressurization at the base (h2) of the viscous degassed magma at the top of the magma column (h1 and h2) in response to the exponential growth (black line) of the gas (Eq. 2). c When the pressure induced by the highly vesiculated magma overcomes the tensile strength of the viscous magma mush42, 44, fragmentation occurs (zi).
