Fig. 7: Depths where the maximum packing fraction (ϕm) is achieved.
Considering a constant aspect ratio (rp = 4), typical of euhedral crystallization (black line), ϕm will not be achieved at depth and dike can propagate to the surface feeding an eruption. Only with cooling rates >2 × 10−3 °C s−1, the maximum packing fraction may be achieved close to the surface. Considering minimum aspect ratios (rp min) achievable at ∆T ≥ 30 °C, typical of incipient dendritic crystallization (blue line), ϕm is achieved at depth only if cooling rates >1.5 × 10−3 °C s−1. Considering maximum aspect ratios (rp max), typical of mature dendritic crystallization (red line), ϕm will be intersected at depth independently of the cooling rate. The yellow dashed line indicates the conditions where ϕm is not achieved and magma is eruptible. Data plotted in Fig. 7 are provided in the Supplementary Table 4.
