Fig. 2

A regime diagram for the brittle failure of viscoelastic magmatic liquids. a–c Constitute the map key (or legend) for navigating through frame d and indicate typical behaviours cast as the evolution of an axial loading stress σ at high, moderate and low timescales of deformation λ, producing a a viscous, b transitional viscous-brittle, and c purely brittle response to loading, respectively. d A regime diagram in which experiments at constant λ are plotted as a function of the relaxation time λ_r and coloured according to the macroscopic response observed (see map key at left a–c). Results of this study are compared with a reanalysis of previous experimental results for magmatically-relevant pure liquids^22,26,35. All data are consistent with viscous behaviour at Wi < 0.01 and brittle behaviour at \({\mathrm{Wi}} \,\,\gtrsim \,\,0.04\). Where G_∞ was not known, we have taken 10¹⁰ Pa for silicate liquids^28,30